The rugged terrain of western Oaxaca, shaped by the Sierra Mixteca mountains, features deep valleys and steep hills rising above 2,000 m. Despite varied environmental conditions, this region has been a cultural and demographic heartland for over 3,000 years (Borejsza et al. Reference Borejsza, Joyce, Lohse, Rodríguez López, Lohse, Borejsza and Joyce2021; Flannery and Marcus, eds. Reference Flannery and Marcus1983; Pérez Rodríguez Reference Pérez Rodríguez2013; Spores Reference Spores1984; Winter Reference Winter1989). By 1500 BC, the first villages emerged, with archaeologists inferring the presence of social inequality by 900–300 BC at sites such as Tayata, Etlatongo, and Nuundaa (Balkansky et al. Reference Balkansky, de Jesús Nava Rivera and Teresa Palomares Rodríguez2009; Blomster Reference Blomster2004:113; Byland Reference Byland1980:135–140). Around 300 BC, populations consolidated on hilltops including Cerro Jazmín, Huamelulpan, Yucuita, and Monte Negro, marking the start of the Ramos phase (Table 1; Figure 1).
The state of Oaxaca with the location of several sites mentioned in the text.
Monte Negro Chronology.
Table 1 Long description
Chronological crosswalk linking broad Mesoamerican periods to named phases in Western Oaxaca and the Valley of Oaxaca across time ranges from about 1500 to 1400 B. C. through A. D. 1000 to 1521. In Mesoamerica, the sequence runs Middle Formative, Late Formative, Terminal Formative, Early Classic, Late Classic, Early Postclassic, and Late Postclassic. Western Oaxaca entries include Guadalupe (about 1400 to 1100 B. C.), Cruz C (about 1100 to 900 B. C.), Cruz D (about 700 to 500 B. C.), Early Ramos (about 500 to 300 B. C.), Late Ramos (about 100 B. C. to A. D. 200), Las Flores (A. D. 500 to 800), and Early Formative Natividad listed alongside the A. D. 1000 to 1521 row. Valley of Oaxaca emphasizes Monte Albán phases: Rosario (about 1100 to 900 B. C.), Monte Albán Ia (about 700 to 500 B. C.), Monte Albán Ic (about 500 to 300 B. C.), Monte Albán II (about 100 B. C. to A. D. 200), Monte Albán IIIa (A. D. 200 to 500), Monte Albán IIIb (A. D. 500 to 800), Monte Albán IV (A. D. 800 to 1000), and Monte Albán V plus Cruz A and B in the latest row. Several rows contain blanks or irregular text entries (for example, “San José,” “Tierras Largasasdf,” and “Espiridión”) without associated dates or regional phases, so those items should be treated as incomplete or unassigned in this transcription.
Sources: Based on Balkansky et alia (Reference Balkansky, Pérez Rodríguez and Kowalewski2004) and Pérez Rodríguez (Reference Pérez Rodríguez2013).
The settlement shifts associated with the Ramos phase reflect a dramatic period of reorganization in western Oaxaca. In a trend toward regional political hierarchization, smaller hamlets and villages became subservient to primary centers (Balkansky Reference Balkansky1998; Gaxiola González Reference Gaxiola González1984:15–16; Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:336; Plunket Reference Plunket1983:359–372; Robles García Reference Robles García1988:1–14; Spores Reference Spores1972:175–182, Reference Spores, Flannery and Marcus1983a; Winter Reference Winter1982:12–15). The move to hilltops also signals heightened interpolity tension, though the nature of these dynamics remains debated. Most scholars argue that Monte Negro and its contemporaries were rival centers that traded but also engaged in raiding and episodes of hostility (Winter Reference Winter1989:38), militarization (Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:301), and warfare (Workinger and Joyce Reference Workinger, Joyce, Orr and Koontz2009), likely linked with elite prerogatives (Joyce Reference Joyce, Scherer and Verano2014:129–135). Others, however, interpret relationships, particularly among elites, as an “alliance network” (Spores Reference Spores, Flannery and Marcus1983a:123). As explored in the discussion section, the possible influence of Monte Albán as a catalyst for these developments remains an intriguing and open question (Balkansky Reference Balkansky1998; Flannery Reference Flannery, Flannery and Marcus1983; Joyce Reference Joyce, Brown and Stanton2003:53–63; Marcus and Flannery Reference Marcus and Flannery1996:198; Pérez Rodríguez Reference Pérez Rodríguez2013:83–87; Spores Reference Spores and Kent1983b:77).
Architectural innovations suggest that religious and civic life also underwent transformation during the Ramos phase. Monumental construction increased dramatically compared to Late Cruz phase sites, supported through systems of corvée labor. Although sites such as Huamelulpan, Yucuita, Cerro Jazmín, and Monte Negro each present distinct layouts (Balkansky et al. Reference Balkansky, Pérez Rodríguez and Kowalewski2004:Figure 11; Pérez Rodríguez et al. Reference Pérez Rodríguez, Anderson and Neff2011:Figure 3; Plunket Reference Plunket1983:Figure 10), they all exhibit clusters of plazas and ceremonial buildings with adjacent elite residences. As with other regions in Oaxaca, emerging elites likely sought to appropriate ritual practices to consolidate authority within these new architectural settings (Joyce Reference Joyce2009:193; Marcus Reference Marcus, Sharer and Grove1989:154; Marcus and Flannery Reference Marcus and Flannery2004:18259). Household-level ritual continued, as explored below, but elite and specialist activities expanded in both scale and diversity, incorporating exotic goods, animal sacrifice, feasting, and ballcourts (Pérez Rodríguez Reference Pérez Rodríguez2013).
As the first intensively studied Late Formative site in western Oaxaca, Monte Negro remains central to understanding Ramos phase transformations. In 2023 and 2024, the lead author directed the first excavations outside of the monumental sector in diverse contexts, including a plaza, households, and in the vicinity of a previously unknown series of walls about 1 km from the main site. With full analysis of these recent excavations to come in a forthcoming dissertation, the findings presented here build on nearly a century of archaeological work at Monte Negro. They serve to refine the site’s chronology, illuminate neighborhood-level organization, and offer new perspectives on its regional role and enduring symbolic significance.
Previous Work at Monte Negro
During a visit to Santiago Tilantongo in 1936, Alfonso Caso was guided by local residents to the remains of an ancient settlement atop a nearby mountain range. The site’s defensible mountaintop location provoked comparisons to Monte Albán—where Caso had excavated since 1931—and surface ceramics closely resembled its Late Period I pottery. Believing the settlement might hold clues about Monte Albán’s origins, he organized a team of Mexican archaeologists including Jorge Acosta, Martín Bazán, Juan Valenzuela, Javier Romero, and Alberto Ruz to excavate Monte Negro’s monumental sector. Between 1937 and 1940, the team uncovered numerous buildings, patios, and plazas, along with tombs, burials, and offerings (Acosta and Romero Reference Acosta and Romero1992; Caso Reference Caso1938, Reference Caso1942).
Contrary to early expectations, Monte Negro did not predate Monte Albán, and the latter’s origins were ultimately traced locally to the Valley of Oaxaca. Even so, parallels in ceramics, architecture, and funerary practices emerged between the two sites (Acosta and Romero Reference Acosta and Romero1992; Bernal Reference Bernal and Willey1965; Caso Reference Caso1942; Flannery Reference Flannery, Flannery and Marcus1983). Weighing these similarities against Monte Negro’s significantly smaller scale, Ignacio Bernal suggested that “the Monte Negro culture which is related to Monte Alban I appears to be less complete and less developed” (Bernal Reference Bernal and Willey1965:798), a prescient observation with which archaeologists continue to grapple.
Javier Romero and Bioarchaeological Studies
Beyond its short occupational history—which did not appear to outlast Period Ic at Monte Albán—Monte Negro’s bioarchaeological evidence stood out as especially enigmatic. Excavations by Caso and colleagues recovered the remains of 28 individuals whose physical traits differed from any other known Oaxacan population (Acosta and Romero Reference Acosta and Romero1992; Romero Reference Romero, Comas, Hurtado, Maldonado-Koerdela and Marquina1951). These differences ranged from biological—the individuals were taller than known populations and with different cranial morphology—to cultural, as many presented annular cranial modification and some trepanation and dental inlays.
Recently, Romero’s original analyses of elite burials have been reexamined by biological anthropologists. Unexpectedly, Serrano Sánchez and Corona Sánchez (Reference Serrano Sánchez, Sánchez, Herrera and Lira2020) and Corona Sánchez (Reference Corona Sánchez2024) propose connections with prehispanic Aymara populations of Peru and Bolivia. While most scholars believe that Monte Negro’s founding population came from somewhere closer—including Cruz phase settlements in the local Santiago Tilantongo Valley (Balkansky et al. Reference Balkansky, Pérez Rodríguez and Kowalewski2004)—more information is needed to examine the origins of the individuals buried at Monte Negro. Excavations in 2023 and 2024 increased the sample size, but moving the conversation forward will likely require data from new approaches (e.g., isotopic and paleogenomic), as well as excavations at local antecedent sites to assess biological and cultural continuity.
Later Assessments of Monte Negro
Monte Negro stayed on the radar of archaeologists following Caso’s work. Marquina (Reference Marquina1951) included Monte Negro in his study of prehispanic architecture. Flannery (Reference Flannery, Flannery and Marcus1983) later reevaluated the mountaintop site in light of known militaristic incursions by Monte Albán into the nearby Cuicatlán Cañada (Redmond and Spencer Reference Redmond, Spencer, Arkush and Allen2006), proposing that Monte Negro might have served as an outpost of the expanding Zapotec state.
During archaeological survey in the Santiago Tilantongo valley, Bruce Byland and John Pohl visited Monte Negro. Based on aerial photographs, they produced a schematic map of the site and made the first population and area estimates for the site, at 35 ha and 2,000 people, respectively (Byland and Pohl Reference Byland and Pohl1994:53). Describing the site as “categorically different from any other Ramos phase site known anywhere in the Mixteca” (Byland and Pohl Reference Byland and Pohl1994:54), they also propose that one of the danzante figures at Monte Albán may refer to conquest of a nearby site, suggesting that Oaxaca’s first urban center wielded influence in the Sierra Mixteca during this time. While the specific danzante in question has not been reevaluated, the debate continues around the carved slabs at Monte Albán and their implications for Monte Albán’s territorial reach (e.g., Marcus Reference Marcus and Nicholson1976, Reference Marcus2020:121–191; Marcus and Flannery Reference Marcus and Flannery1996:195–207; Redmond and Spencer Reference Redmond, Spencer, Arkush and Allen2006) or alternative meanings (e.g., Carter Reference Carter2017; Urcid and Joyce Reference Urcid, Joyce, Tsukamoto and Inomata2014).
Mapping by the University of Leiden
A University of Leiden team mapped 40.5 ha of Monte Negro in 2000, documenting its best-preserved architecture and evaluating preservation (Van Broekhoven et al. Reference Van Broekhoven, Geurds and García García2000). Their work, complementary to INAH maintenance activities taking place at the same time (Matadamas Reference Matadamas2000), resulted in a detailed reconstruction of the monumental sector, which is presented in Geurds’s (Reference Geurds2007) dissertation. A publication by Geurds and Jansen (Reference Geurds, Jansen, Mastache, Cobean, Cook and Hirth2008) interprets Monte Negro’s monumental architecture through Indigenous Mixtec notions of sacrality and rulership. The map presented here builds on the reconstruction of monumental buildings by the 2000 team.
Regional Settlement Surveys and Defensive Relocation
Systematic surveys of western Oaxaca’s highland valleys, carried out since the 1960s, have been crucial for reconstructing regional dynamics of the Late Formative (Balkansky et al. Reference Balkansky, Kowalewski, Rodríguez, Pluckhahn, Smith, Stiver, Beliaev, Chamblee, Heredia and Prez2000; Byland Reference Byland1980; Byland and Pohl Reference Byland and Pohl1994; Finsten Reference Finsten, Peregrine and Feinman1996; Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009; Plunket Reference Plunket1983; Spores Reference Spores1972). The surveyed areas indicate widespread demographic relocation to hilltop locations at the onset of the Ramos phase, accompanied by unprecedented demographic growth and architectural works. In the Nochixtlán Valley, the population of Xacañi relocated to Cerro Jazmín, where 4,000–8,000 people settled an area of roughly 86 ha (Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:31–34; Pérez Rodríguez et al. Reference Pérez Rodríguez, Anderson and Neff2011). Yucuita experienced similar explosive growth, with a population that grew approximately 430% to as many as 3,000 inhabitants (Plunket Reference Plunket1983:359; Winter Reference Winter1982:12). Nearby, a portion of Etlatongo’s population also relocated to a previously unoccupied hilltop (Blomster Reference Blomster1998a:638). In a valley to the west, Huamelulpan expanded from 6 ha in the Late Cruz phase to 155 ha by the start of the Ramos phase (Balkansky Reference Balkansky1998).
Survey in the Santiago Tilantongo Valley, home to Monte Negro, revealed a similar trajectory. Earlier in the Formative period, the valley’s principal settlement shifted from Early Cruz phase Diuxi to the slightly higher and Late Cruz phase La Providencia (Balkansky et al. Reference Balkansky, Pérez Rodríguez and Kowalewski2004). Then, around 300 BC, 91.57 ha La Providencia was abandoned in favor of the Monte Negro site, several kilometers away and nestled on a mountaintop 400 m above the valley floor (Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:69–70; Supplementary Figures 1 and 2).
Mapping Monte Negro
Building on previous mapping efforts by Caso and colleagues (Acosta and Romero Reference Acosta and Romero1992:29–71), Byland and Pohl (Reference Byland and Pohl1994:55), and Van Broekhoven et al. (Reference Van Broekhoven, Geurds and García García2000), Christopher Glew made the first complete map of Monte Negro in 2002. After conducting a topographic survey of the entire site at a scale of 1:1000, Glew recorded all mounds, walls, stone foundations, terraces, ramps, and other features visible on the surface. These efforts added significant detail in the areas outside of the monumental core. Minor additions were made in 2023 and 2024, and our current map covers 85 ha (Figure 2), a slight increase over the 77.76 ha estimated by Balkansky et al. (Reference Balkansky, Pérez Rodríguez and Kowalewski2004:44).
Site map of Monte Negro, which builds on efforts by Acosta and Romero (Reference Acosta and Romero1992), Balkansky et alia (Reference Balkansky, Pérez Rodríguez and Kowalewski2004), Byland and Pohl (Reference Byland and Pohl1994), and Van Broekhoven et alia (Reference Van Broekhoven, Geurds and García García2000). (Color online)
Figure 2 Long description
Map of Monte Negro detailing various archaeological features and elevation contours. Structures are marked with black lines, terraces with green triangles, incomplete foundations with green squares and plazas with black stars. Elevation is indicated by red contour lines labeled as 2750 and 2600 meters above sea level (MASL). The map includes a scale bar of 250 meters and a north arrow for orientation. The distribution of features is concentrated in the central area, with structures and terraces densely clustered, while plazas are scattered throughout. Elevation contours suggest a varied terrain, with higher elevations in the northwest and lower elevations in the southeast.
Site-Level Organization
The founders of Monte Negro settled on a triangular ridge extending north from Cerro Negro, a mountain cluster at the head of the Santiago Tilantongo Valley. Cerro Negro lies at a southeastern bend in what Kowalewski et al. (Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:76) call the “Sierra de Nochixtlán,” a longer range that begins near the modern town of Yanhuitlán. Although not the tallest peak in the range, Cerro Negro offered an expansive, flat summit suitable for large buildings and commanding views to the north, northeast, and northwest.
From the summit, three ridgelines extend north, northeast, and east. GIS analyses suggest that Monte Negro’s social organization contoured to this natural topography, producing at least four distinct sectors. We have defined these as (1) the flat, mountaintop “Monumental Sector,” (2) the broad slopes of the “East Sector,” (3) the broad slopes of the “North Sector,” and (4) the steeper slopes of the “Northeast Sector.” In addition to these sectors, which saw diverse architectural works, large surrounding drainages were transformed into massive lama-bordo, or check-dam, terraces, among the most extensive agricultural systems ever built in western Oaxaca (Pérez Rodríguez Reference Pérez Rodríguez, Cliggett and Pool2008:97) and still in use today.
Neighborhoods—defined as areas of recurrent face-to-face interaction (Smith Reference Smith2010)—are widely recognized cross-culturally as meaningful units of social life (e.g., Talen Reference Talen2018; York et al. Reference York, Smith, Stanley, Stark, Novic, Harlan, Cowgill and Boone2011). However, identifying units of community organization presents inherent challenges in archaeological contexts (Marcus Reference Marcus, Canuto and Yaeger2000). In western Oaxaca, historic Mixtec models of intermediate organization offer valuable points of comparison, but their application to earlier periods is problematic. As such, neighborhoods remain poorly understood before the Classic period (Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:337–339). Even so, tracing the emergence of such social units is essential for understanding the sociopolitical transformations that defined the Late Formative.
Based on surface architecture (following Thompson et al. Reference Thompson, Walden, Chase, Hutson, Marken, Cap and Fries2022; see also Whittington and Frykholm Reference Whittington and Frykholm2025), we used the Kernel Density and Average Nearest Neighbor tools in ArcGIS Pro to identify potential neighborhoods at Monte Negro (Figure 3). In this case, the short-lived nature of the settlement caters to such sitewide analyses, in contrast to longer-lived sites where construction and ceramics span multiple phases. Combined with artifact distributions, our spatial analyses suggest the presence of socially meaningful units, even if the ways in which residents defined or experienced them remain unknowable. In the following sections, we examine each sector in greater detail.
A kernel density map for architectural features at Monte Negro. The dashed lines indicate hypothetical neighborhoods. (Color online)
Figure 3 Long description
Kernel Density map of Monte Negro illustrating architectural features across different sectors: North, Northeast, East and Monumental. The map uses density values to indicate the concentration of features. High Kernel Density Value areas are marked in dark shades, while low density areas are lighter. Structures are outlined in red and terraces are marked in green. The map includes a scale bar indicating 250 meters and a north arrow for orientation. The density values highlight clusters of architectural features, with notable concentrations in the Monumental and Northeast sectors.
Intensive Surface Collection
After mapping all of Monte Negro’s visible architecture, Glew conducted an intensive surface collection program in a random sample of 100 m2 units across the site, excluding most of the Monumental Sector, which had been excavated between 1937 and 1940 and is open to the public. All surface artifacts—pottery, chipped and ground stone, burned clay, shell, mica—were collected during the survey. The 216 units represent approximately 2.54% of the total site area (Supplementary Figure 3). Over the course of mapping the site, Glew also recorded opportunistic finds of artifacts including metates, manos, braziers, and figurines.
Interpreting patterns from surface collections presents inherent challenges and must be approached thoughtfully (Flannery Reference Flannery and Flannery1976a:51–61). At Monte Negro, erosion and modern agricultural activity have significantly affected artifact distributions. However, the site’s particular topography also serves as a mitigating factor, preventing material displacement from one ridge to another. As a result, interpretations at a coarse, sector-level resolution offer valuable insights into broader spatial trends.
Patterns we observed from surface collection data include
1. Metates and manos, ground-stone tools important for food preparation, occur across the site, with marked concentrations in the four sectors.
2. The Northeast Sector exhibits hot spots in multiple domestic ceramic categories, pointing to an extensive residential area.
3. Concentrations of chipped stone and axes in the Northeast and East Sectors likely reflect household-level economic activity, or multicrafting.
4. Ceramic braziers and figurines are more frequently encountered away from ceremonial plazas and in the context of domestic architecture, suggesting that ritual practices were practiced on a household level in these areas.
Kernel Density and Hot Spot Analysis
Integrating surface artifact distributions with spatial and architectural data allowed us to further explore patterns related to social organization and economic and ritual activity at Monte Negro. Specifically, kernel density was applied to the opportunistic finds of conspicuous artifacts encountered in the mapping of the site. The tool works by producing a smooth surface where density is highest and gradually decreases with distance (ESRI 2025a). In contrast, hot spot analysis works by identifying statistically significant clusters of high or low artifact or attribute densities by comparing local values to expected distributions (ESRI 2025b). We applied this tool to artifacts collected in the surface survey units, isolating attributes like ceramic form and surface decoration, to determine where statistically significant clusters appeared across the site.
A kernel density map of manos and metates, kitchen tools used for grinding, reveals concentrations within the four previously defined sectors (Figure 4). Unsurprisingly, there were households in all four sectors that participated in everyday food preparation. The Northeast Sector, in particular, stands out for its domestic patterning. This sector presents hot spots for multiple artifact classes including ollas and bowls (as represented by diagnostic rim sherds), ceramics associated with food preparation, storage, and consumption (Figure 5; Supplementary Figure 4). By contrast, the East Sector yielded surprisingly little cooking and serving ware in surface survey—perhaps a reflection of its lower residential density—though excavations in 2024 did document multiple residences. Here, as in the Northeast Sector, high densities of chipped stone artifacts (Figure 6) nevertheless suggest household-level economic production. Isolated axe finds, most densely concentrated between the Northeast and East Sectors (Supplementary Figure 5), further point to multicrafting activities being carried out.
A kernel density map for isolated metate and mano finds points to four main concentrations, generally aligning with the proposed four neighborhood sectors. (Color online)
Figure 4 Long description
Kernel density map showing isolated finds of metate and mano, with density values ranging from high to low. High kernel density values are marked in dark shades, while low values are in lighter shades. The map includes labeled structures and a scale bar indicating 250 meters. The distribution shows several concentrated areas, suggesting significant activity or usage in those regions. The map is oriented with a north arrow.
Hot spots for olla rim sherds are found in the Northeast Sector, with presence noted across the rest of the site, particularly in the North Sector. (Color online)
Figure 5 Long description
A map depicting archaeological structures with elevation marked in meters above sea level (MASL). The legend indicates two elevation levels: 2150 and 2700 MASL. Structures are represented by green squares, with hot spots marked in red, indicating 99 percent confidence. White squares denote areas present but not statistically significant. The map includes a scale bar of 250 meters and a north arrow for orientation. The distribution shows clusters of structures, with notable hot spots in the northeastern section.
Hot spots for chipped stone are found in the Northeast and East Sectors, with presence noted in collection units across the site. (Color online)
Figure 6 Long description
A map depicting the distribution of structures with hot spots indicated by confidence levels. The legend includes ′Hot Spot with 99 percent confidence′ marked in red, ′Hot Spot with 95 percent confidence′ in orange, ′Hot Spot with 90 percent confidence′ in green and ′Present, not statistically significant′ as white squares. Elevation is shown in meters above sea level (MASL) with contour lines at 2300 and 2150 meters. The map includes a scale bar of 250 meters and a north arrow for orientation. Structures are outlined and hot spots are clustered primarily in the central and eastern areas, with varying confidence levels indicated by color coding.
Ritual artifacts recovered during the surface survey were unevenly distributed across the site. Brazier and incensario fragments—ceramic artifacts associated with burning—show strongest concentrations southwest of the monumental core, as well as in the Northeast Sector (Supplementary Figure 6). Similarly, figurines, which might have played a role in household rituals, are most densely clustered in the Northeast Sector (Figure 7), a pattern explored in the next section.
A kernel density map for isolated figurine finds shows heavy concentration in the Northeast Sector. (Color online)
Figure 7 Long description
Figurine Isolated Finds thematic map with a legend for Structure, High Kernel Density Value and Low Kernel Density Value. Numerous small point symbols mark isolated finds across the mapped site area. Structure is shown as outlined shapes distributed mainly across the central portion of the map. Kernel density is shown as shaded hotspots around the points. One strongest hotspot appears in the upper central area of the map. Additional, weaker hotspots appear across the central area, including a broad hotspot toward the lower left and another toward the lower right. Map elements include a scale bar labeled 250 m and a north arrow labeled N, with the arrow pointing upward.
Plazas and Social Organization
Monte Negro contains six small, square plazas, first numbered by Van Broekhoven et al. (Reference Van Broekhoven, Geurds and García García2000). Five are arranged along a roughly east–west axis (Geurds Reference Geurds2007:64). Four of these are in the Monumental Sector, possibly associated with the paved “avenue” documented by Caso, which also runs east–west. Plaza 5, excavated in 2023, is located 180 m downslope in the East Sector. Plaza 6, the northern outlier, occupies a flat ridge roughly 350 m beyond the Monumental Sector.
Each plaza consists of a sunken open space framed by four cardinally oriented buildings. Without exception, the largest and most elaborate structure is on the east side. Plaza buildings in the Monumental Sector are largest volumetrically, and encircle an average 571.75 m2 of central open space. By comparison, Plazas 5 and 6 have smaller open spaces of 375 m2 and 328 m2. The prominence of plazas at Monte Negro indicates that these spaces were integral to the settlement’s original layout and foundational to daily life. Their placement across multiple sectors further suggests that community coalesced around several architectural nodes rather than a single center.
Decentralized layouts are widely attested across Ramos phase centers, holding important implications for political organization and urban development (Balkansky Reference Balkansky1998; Marcus Reference Marcus, Vogt and Leventhal1983). At Huamelulpan, monumental construction was dispersed across five separate foci, segmented by the local topography (Winter Reference Winter1984:11). Gaxiola González (Reference Gaxiola González1984:80) interprets this dispersed public architecture and the adjacent residential zones as “integrative mechanisms” for urbanism. At Yucuita, Spores reports “unprecedented emphasis on elaborate, highly organized ceremonialism, with major structural complexes constructed” (Reference Gaxiola González1984:24). Plunket believes these ceremonial precincts at Yucuita—with small resident populations, plazas, and “temple-like” structures—“may have functioned as the administrative and ceremonial foci for sub-areas” (Reference Plunket1983:75, 102). Meanwhile, at Cerro Jazmín, rapid demographic growth coincided with the construction of “several clusters of monumental buildings and plazas that were the sites of specialized economic, political, and ritual activity” (Pérez Rodríguez et al. Reference Pérez Rodríguez, Anderson and Neff2011:84). These sectors are surrounded by terraced residential areas that reveal evidence of craft production, but each presents unique accessibility and function (Pérez Rodríguez et al. Reference Pérez Rodríguez, Anderson and Neff2011:89).
Even Monte Albán, whose Main Plaza defined the city’s epicenter during the Classic period, probably began more heterogeneously. Blanton (Reference Blanton2004:37) argues that three neighborhoods initially developed along the edges of the Main Plaza, perhaps reflecting different ethnic groups. Recent geophysical surveys offer supporting evidence that Monte Albán’s earliest layout consisted of smaller, dispersed clusters of buildings and open spaces (Levine et al. Reference Levine, Hammerstedt, Regnier and Badillo2021).
Such cases suggest that neighborhoods in Oaxaca’s first proto-urban centers formed around discrete clusters of monumental buildings. Monte Negro, too, had residential buildings adjacent to plazas, suggesting that different corporate groups may have held semiautonomous authority in these spaces, perhaps an early iteration of Marcus’s (Reference Marcus, Vogt and Leventhal1983) “multiple nuclei” urban model. Plazas were clearly fundamental to Monte Negro’s overall organization, but their importance, we believe, was not only logistical. Plazas were key ideological spaces through which emerging elites sought to appropriate sacred relationships and legitimate new forms of authority.
Plazas and Ritual
As Norwood and Smith (Reference Norwood and Smith2022) observe, plazas in Mesoamerica integrated society. They were inherently multifunctional, witnessing diverse activities including political assemblies, ritual performances, and daily gatherings. In the Late Formative, when such spaces were taking on new dimensions, plazas likely carried heightened ideological weight. At La Laguna in Tlaxcala, for example, Carballo (Reference Carballo2012) demonstrates how ritual practices evolved in the context of—and further promoted—growing social complexity. Joyce similarly characterizes 700–100 BC as “a time of major changes in power relations in Oaxaca and other regions of Mesoamerica that were in part driven by struggle over peoples’ relations to the sacred” (Reference Joyce, Robb and Dobres2000:75). By controlling access to ceremonial spaces and elaborating existing rituals that probably involved powerful ancestors, elites positioned themselves as mediators between ordinary people and the supernatural (Marcus Reference Marcus, Sharer and Grove1989). In the Formative period, ritual acts and spaces thus became ideological tools of authority.
Archaeological findings suggest that this process was happening at Monte Negro. Caso and colleagues’ excavations of the site’s monumental core revealed four plazas as well as civic-ceremonial and other monumental buildings associated with elite residences and burials (Acosta and Romero Reference Acosta and Romero1992). Marcus and Flannery (Reference Marcus and Flannery1996:168) interpret the roofed corridors of Monte Negro’s monumental buildings as passageways for chiefly individuals—privileged access to sacred spaces. Adjacent to Plaza 3, the Temple T-South building presented Ofrenda 1, two 14 cm bifacial obsidian daggers (Acosta and Romero Reference Acosta and Romero1992:125) similar to knives later used to remove the hearts of human sacrificial victims (Marcus and Flannery Reference Marcus and Flannery1996:167). Temple T’s eastern steps also bear a triangular “blood drop” motif, further evoking sacrifice (Flannery Reference Flannery, Flannery and Marcus1983). As archaeologists have documented, bloodletting, particularly among elites, was central to ritual life and worldview in Oaxaca and Mesoamerica more broadly (e.g., Boone Reference Boone1984; Flannery Reference Flannery and Flannery1976b; Grove Reference Grove1987; Joyce Reference Joyce, Robb and Dobres2000; Schele and Miller Reference Schele and Miller1986:175–208).
Most recently, work in Plaza 5 (Supplementary Figure 7) uncovered human burials, sacrificed dogs, ceramic offerings, deer antlers, and the remains of textiles burned in limestone cavities (Frykholm Reference Frykholm2023). Such practices resonate with emerging regional traditions—animal sacrifice, feasting, and ballgames (Pérez Rodríguez Reference Pérez Rodríguez2013)—that elites adopted and elaborated locally.
As was probably the case at other Formative period sites, the plazas at Monte Negro embodied a fundamental paradox. They were spatially and socially integrative spaces distributed in three sectors across the site that also, we believe, served as exclusionary stages where elites controlled important rituals. In this sense, they simultaneously fostered social cohesion and reinforced stratification (Joyce and Winter Reference Joyce and Winter1996). Nevertheless, this model was not consistent across Monte Negro, as the Northeast Sector conspicuously lacks a plaza. Based on surface collection data, it is possible that household-level ritual practices played a more prominent role in this sector.
The Northeast Sector
The Northeast Sector is the most isolated of the four identified “neighborhoods” at Monte Negro. It is furthest from the monumental core and on a relatively steep hillside. Lama-bordo terraces in the small drainages on either side separate it from the East and North Sectors. Our mapping of this sector revealed no monumental construction or plazas, even while the steeper terrain would not have precluded such construction. The smaller, less elaborate structures recorded here, considered alongside the abundance of utilitarian ceramics and proximity to agricultural terraces, point to this sector being a neighborhood of commoners. While we do not know if residents here had access to the ceremonial spaces of other sectors, the absence of a plaza within the Northeast Sector likely points to social differentiation at Monte Negro.
Nevertheless, ritual life in the Northeast Sector was clearly not absent. Alongside high representation of brazier and incensario fragments, opportunistic surface collections reveal the highest density of ceramic figurines in this sector. Figurine use was widespread across multiple Mesoamerican regions during the Formative period, with archaeologists convincingly tying their use to evolving social dynamics (Blomster Reference Blomster1998b; Cyphers Guillén Reference Cyphers Guillén1993; Drennan Reference Drennan and Flannery1976; Flannery and Marcus Reference Flannery and Marcus2005:88–93; Harlan Reference Harlan and Grove1987). In the Valley of Oaxaca, Marcus (Reference Marcus1998) documented the importance of figurines in domestic rituals, particularly among women, who used them to communicate with ancestors. In the context of solidifying hereditary rank and the emergence of ritual specialists, household figurines might have helped negotiate social change. In this context, the concentration of figurines in the Northeast Sector of Monte Negro may reflect household-level ceremonies that compensated for the absence of a formal plaza. As Joyce (Reference Joyce, Robb and Dobres2000) observes, commoners were not wholly dependent on elites for engagement with the sacred; female figurines may even represent household-level resistance to elite appropriation of ritual (King Reference King1988:43).
Other Discoveries
A least-cost analysis model based on topography and land cover (White and Barber Reference White and Barber2012) suggests that Monte Negro and the Santiago Tilantongo Valley were not well integrated into western Oaxaca’s main mobility corridors. Sites such as Yucuita, Cerro Jazmín, Etlatongo, and Huamelulpan, meanwhile, are found in more accessible valleys. These valleys also present a higher density of secondary centers—what Kowalewski et al. (Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:24–27) describe as large villages or towns (Figure 8). In contrast, the Tilantongo Valley has few other Ramos phase settlements. While there is not yet complete survey coverage to the south of Monte Negro, existing results, considered alongside Cerro Negro’s rugged setting, underscore the site’s dramatic isolation.
Settlements contemporaneous with Monte Negro (based on surveys by Balkansky et al. Reference Balkansky, Kowalewski, Rodríguez, Pluckhahn, Smith, Stiver, Beliaev, Chamblee, Heredia and Prez2000; Byland Reference Byland1980; Byland and Pohl Reference Byland and Pohl1994; Finsten Reference Finsten, Peregrine and Feinman1996; Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009; Plunket Reference Plunket1983; Spores Reference Spores1972).
Slope, elevation, and intersite visibility all contribute to a site’s defensibility. At Monte Negro, the north, east, and west flanks drop steeply, but the southeast is more accessible, where the Cerro Negro massif continues for several kilometers. If the ridge is gained from this direction, it offers a flat—even downhill—final approach to Monte Negro. Investigating this potential vulnerability in 2023, a pedestrian survey documented two previously unrecorded walls about 1 km southeast at a bottleneck along Cerro Negro (Figure 9). Wall 1 extends 225 m with a 3.1 m gap at the ridge crest, flanked by a 5.06 m “curtain” wall set 1.81 m behind. Wall 2, further downslope, runs 103 m and includes at least one staircase.
Wall 1 (top) and Wall 2 (bottom) after the removal of moss from the hewn limestone blocks. The “curtain wall” is out of view in the upper right-hand corner. Photograph courtesy of Soren Frykholm. (Color online)
These features could have served an administrative (traffic-control) or defensive role. The gap at the ridge crest would have permitted controlled access with the extended walls providing defensive cover against attack from the southeast. Excavations, however, raised questions about their temporal relationship to Monte Negro’s Late Formative occupation. The coarse limestone masonry is different from Monte Negro’s finely cut blocks, and artifacts were sparse and nondiagnostic. Beyond this, the two charcoal deposits recovered during 64 m2 of excavations taken to limestone bedrock yielded Late Postclassic and Early Colonial radiocarbon dates. While acknowledging the problem of dating walls without embedded and datable materials, we tentatively conclude that these fortifications postdate Monte Negro’s Ramos phase, perhaps by more than a millennium.
Late Postclassic Activity at Monte Negro
If built during the Late Postclassic, as suggested by the radiocarbon dates, the walls would fall within broader architectural practices in western Oaxaca during this time (Pérez Rodríguez and Heredia Espinoza Reference Pérez Rodríguez and Heredia Espinoza2020:182–188). Though Monte Negro had long been uninhabited at that point, historical accounts portray ancestral sites as refuges in times of upheaval. Friar Francisco de Burgoa described Monte Negro as a defensive stronghold (Reference Burgoa1989 [1674]:275–276), and Manuel Martínez Gracida (Reference Martínez Gracida1883:24) later recorded oral traditions in Santiago Tilantongo that recounted alliances with leaders from Achiutla and mountaintop fortresses that served in times of “combat.” Remarkably, modern oral history suggests that Monte Negro was used as a refuge as recently as the Mexican Revolution.
An alternative is that the walls held ritual or symbolic functions. Evidence of Classic and Postclassic ritual at the site indicates that Monte Negro retained ancestral significance long after its abandonment (Balkansky et al. Reference Balkansky, Pérez Rodríguez and Kowalewski2004; Caso Reference Caso1942). At nearby Yucundaa, Spores and Robles García (Reference Spores, García, Spores and Robles García2017:43–44) interpret Postclassic walls as ceremonial pathways to caves. The Cerro Negro walls may have played a similar role, as they are situated between Monte Negro and Vehe Ndute (“House of Water”), a cave reported by Geurds and Jansen (Reference Geurds, Jansen, Mastache, Cobean, Cook and Hirth2008:397) that is still venerated by local communities today.
Studies of Indigenous documents from western Oaxaca would support either interpretation. Many scholars identify the black hill on page 22 of the Codex Tonindeye (Nuttall) as Monte Negro (Anders et al. Reference Anders, Maarten and Gabina1992:135–136; Byland and Pohl Reference Byland and Pohl1994:56; Geurds and Jansen Reference Geurds, Jansen, Mastache, Cobean, Cook and Hirth2008; Hamann Reference Hamann2008). The scene depicts a royal Mixtec couple seated on top of a platform built atop Monte Negro, evoking a place of authority and protection. Though Hermann Lejarazu’s (Reference Hermann Lejarazu2011) alternative identification cautions against a definitive reading, Monte Negro’s probable depiction in Mixtec codices underscores its enduring role as a place of ancestral significance and cultural memory long after its abandonment. More investigation of the walls and the adjacent hilltop, where material culture was also recovered in 2024 test pits, promises to clarify the nature of these enigmatic constructions.
The Olla de Agua Site
On a hillside south of Monte Negro lies a previously unreported site, designated “Olla de Agua” due to its proximity to an open-air water storage tank (Figure 10). After clearing foliage, the site appears to be another plaza with buildings on four sides, though their orientation relative to the other plazas at Monte Negro is unknown. The leveled open space is much smaller, under 200 m2. Excavations will be required to confirm the site’s temporality and function.
Sites discovered and areas excavated at Monte Negro since 2023. (Color online)
AMS Carbon Dates for Monte Negro
Seventy-five years ago, two samples from burned beams recovered during Caso’s excavations of Temple T were dated with solid carbon methods to the seventh century BC (Arnold and Libby Reference Arnold and Libby1950). However, archaeologists have always regarded these dates with skepticism, as Monte Negro’s ceramics align with those from Monte Albán Period Ic (Flannery Reference Flannery, Flannery and Marcus1983).
Recently, we produced the first radiocarbon dates from Monte Negro via accelerator mass spectrometry at the Laboratorio Nacional de Espectrometría de Masas con Aceleradores (LEMA) physics lab (Table 2). The 13 samples come from secure contexts excavated in 2023 and 2024 and are indicated in Figure 10. These are Plaza 5, Areas A and B (domestic terraces excavated in 2024), and the aforementioned Curtain Wall.
AMS Radiocarbon Dates from Monte Negro.
Table 2 Long description
AMS radiocarbon results are listed by site location, lot and lab code, material and context, radiocarbon age with uncertainty, and calibrated two-sigma calendar ranges. Most samples from Plaza 5 and Ladera Este fall in the late first millennium BC, with calibrated ranges spanning roughly 400 to 1 BC. Plaza 5 includes human collagen from constructive fill and structure contexts dated about 369 to 163 BC and 341 to 46 BC, plus canine collagen tied to offerings dated about 343 to 1 BC and 337 to 43 BC. Plaza 5 also has a charcoal sample from burning on limestone bedrock dated about 170 BC to AD 2. Ladera Este Area A includes an early charcoal hearth dated about 400 to 207 BC and a very recent charcoal sample dated about AD 1686 to 1928. Ladera Este Area B charcoal from hearths and living-floor contexts clusters tightly around about 351 to 46 BC, with one sample extending to about AD 1. Cañada del Lagarto wall-related charcoal is much later, dating to about AD 1299 to 1402 and AD 1451 to 1635. Comparisons across locations suggest a primary late precontact activity phase at Plaza 5 and Ladera Este, alongside later deposits at the wall area and one modern-era charcoal outlier; calibrated ranges and uncertainties mean overlaps do not prove exact contemporaneity.
a These dates have been corrected for isotopic fractionation.
b The radiocarbon age was corrected for variations in atmospheric 14C content using the program OxCal v4.2.4 (Ramsey Reference Bronk Ramsey and Sharen2013), using the calibration curve IntCal20 (Reimer et al. Reference Reimer, Austin, Bard, Bayliss, Blackwell, Ramsey and Butzin2020).
c Plaza 5 carried the designation “Terrace 8” or “T8” during excavations.
With results of recent excavations still forthcoming, radiocarbon dates confirm the long-held view that Monte Negro was a Late Formative settlement, with 300–100 BC remaining a reasonable occupational range. Beyond limited chronological ceramic markers, excavations in 1937–1940 and 2023–2024 did not reveal evidence of multiple construction episodes or major demographic shifts, in contrast to the sequence represented by Huamelulpan “I,” “II,” and “III” (Gaxiola González Reference Gaxiola González1984) and other sites in the Mixteca Alta, supporting Balkansky et alia’s perspective that Monte Negro’s “short-lived existence” was an “urban flashpoint frozen in time” (Reference Balkansky, Pérez Rodríguez and Kowalewski2004:37). Whether Monte Negro was a single- or multigenerational settlement remains unknown, but it is clear that the site’s occupation stands out as unusually brief compared to Yucuita, Huamelulpan, and Cerro Jazmín, all of which persisted into the Terminal Formative.
Importantly, evidence does not suggest that there was another major occupation prior to modern times; this also contrasts with the aforementioned centers, many of which housed significant Postclassic period populations (Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:316–329; Plunket Reference Plunket1983:391–398). However, an anomalous date from Area A, likely associated with a jade offering recovered in 2024, considered alongside the two dated samples from the Curtain Wall, point to persistent (if ephemeral) cultural activity at Monte Negro.
Discussion: Monte Negro’s Origins
The founding of Monte Albán around 500 BC reverberated across Oaxaca and likely beyond. In addition to transforming the political dynamics of the Valley of Oaxaca, Monte Albán’s founding also stimulated demographic growth and cultural change in adjacent regions in subsequent centuries (Balkansky Reference Balkansky1998; Feinman and Nicholas Reference Feinman and Nicholas1990; Joyce Reference Joyce, Brown and Stanton2003; Marcus and Flannery Reference Marcus and Flannery1996; Spencer and Redmond Reference Spencer and Redmond2004; Winter Reference Winter1989:34–38). Alongside the circulation of material goods such as ceramics, political and religious concepts pioneered at Monte Albán diffused widely (Joyce Reference Joyce, Brown and Stanton2003).
The precise nature of Monte Albán’s influence in western Oaxaca during the Late Formative, however, remains unknown. Archaeologists have proposed varied models for Ramos phase developments, including conquest by Monte Albán (Byland and Pohl Reference Byland and Pohl1994; Plunket Reference Plunket1983), synoecism or aggregation into defensible centers in response to external threats (Balkansky Reference Balkansky1998), autonomous local development (Spores Reference Spores1984), and “concordant” change in which frequent interaction between the two regions stimulated parallel growth (Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009). Such diverse models point to the multiplicity of processes at play in the region around 300 BC. Based on the available evidence, we interpret Monte Negro’s founding as an extension of local cultural and demographic trajectories that was nevertheless intimately affected by broader developments radiating from Monte Albán.
Late Formative Period Tensions
Archaeological evidence speaks to a fluctuating and tense sociopolitical environment in core demographic areas of Oaxaca during the Late Formative. New dynamics are reflected in widespread settlement shifts, often to defensible hilltops, and broader trends toward centralization and urbanization (Joyce Reference Joyce, Scherer and Verano2014; Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:336–337; Redmond and Spencer Reference Redmond, Spencer, Arkush and Allen2006; Sherman et al. Reference Jason, Balkansky, Spencer and Nicholls2010; Winter Reference Winter, Escamilla and Castro2005:92). Defensive walls are documented at Monte Albán (Blanton Reference Blanton2004:52–54) and in western Oaxaca at Huamelulpan (Balkansky Reference Balkansky1998:42), Yucuita (Winter Reference Winter1989:37), and Cerro de las Minas (Winter Reference Winter2007:31–33). Rare but striking evidence of violence includes human sacrifice at Yucuita (Spores Reference Spores1984:24), and practices associated with decapitation and trophy skulls at Monte Negro (Romero Reference Romero, Comas, Hurtado, Maldonado-Koerdela and Marquina1951:318) and Huamelulpan (Gaxiola González Reference Gaxiola González1984:51), as well as at Yucunama and Cerro de las Minas (Winter Reference Winter, Escamilla and Castro2005:92).
Unlike the Cuicatlán Cañada, however—where archaeologists have recovered burned buildings, a fortress, a skull rack, and an associated conquest monument at Monte Albán’s Building J (Marcus Reference Marcus1992:175–176; Redmond and Spencer Reference Redmond, Spencer, Arkush and Allen2006)—no unequivocal evidence of subjugation exists in western Oaxaca. This leaves open the possibility that local tensions drove the move to defensible hilltops (Joyce Reference Joyce, Scherer and Verano2014), echoing the rise of intervalley rivalries witnessed several centuries prior in the Valley of Oaxaca (Marcus and Flannery Reference Marcus and Flannery1996:121–126).
Ideological and Material Strategies
This period also witnessed profound ideological and religious changes. While not mutually exclusive with a more defensive interpretation, Monte Albán’s mountaintop establishment has also been proposed as a monumental expression of Otomanguean cosmology—a “mountain of creation,” where the Main Plaza functioned as a stage for sacrifice, offerings, and public reaffirmations of sacred authority (Joyce Reference Joyce, Robb and Dobres2000:81–83).
Such ideological models may help explain the rise of other mountaintop centers such as Monte Negro, where elites adopted other symbolic practices tied to Monte Albán (Flannery Reference Flannery, Flannery and Marcus1983). At Monte Negro, anthropomorphic urns showcase iconographic similarities, while vessels like combed-bottom bowls, eccentric-rimmed plates with fish motifs, tall-necked bottles, and shoe-shaped patojos reflect further affinities to established valley traditions (Balkansky et al. Reference Balkansky, Pérez Rodríguez and Kowalewski2004; Caso Reference Caso1942; Flannery Reference Flannery, Flannery and Marcus1983; Spencer et al. Reference Spencer, Redmond and Elson2008). In architecture, too, Monte Negro’s temples and elite residences recall forms seen at Monte Albán and even earlier at San José Mogote, from shared stairways and platform layouts to transitional buildings that bridged chiefly houses and later royal palaces (Acosta and Romero Reference Acosta and Romero1992:29–71; Flannery and Marcus Reference Flannery, Marcus, Flannery and Marcus1983a, Reference Flannery, Marcus, Flannery and Marcus1983b). Similar patterns appear at sites across western Oaxaca and beyond, where local elites sought legitimacy through access to prestige goods and by adopting ritual practices associated with Monte Albán (Joyce Reference Joyce, Brown and Stanton2003). Formative period developments in western Oaxaca thus show striking parallels to those in the Valley of Oaxaca, though they emerged several centuries later and within the context of smaller mountain valleys that never rivaled the scale of Monte Albán.
Political Shifts and Monte Negro’s Abandonment
By the Terminal Formative, Monte Albán achieved its greatest territorial extent, employing a range of strategies from military conquest to peaceful incorporation (Marcus and Flannery Reference Marcus and Flannery1996:195–207). It had largely incorporated Oaxaca’s entire Central Valley system by this point, although nearby San Martín Tilcajete was a recalcitrant polity that resisted subjugation until the final century BC (Spencer and Redmond Reference Spencer and Redmond2001). Archaeological evidence suggests that polities in adjacent regions experienced a renewed period of instability around 100 BC, reflected in shifting trade networks, changes in governance, and uneven growth and decline among regional centers.
Perhaps like San Martín Tilcajete, some polities in neighboring regions evidently leaned into local identities and traditions during the Terminal Formative. At Cerro Jazmín and in the Río Verde Valley, for instance, imported Valley of Oaxaca graywares were gradually replaced by locally produced variants, and governance and ritual also took on more collective forms, as suggested by communal feasting, more accessible civic spaces, and shared burial practices (Joyce Reference Joyce and Joyce2013; Levine Reference Levine and Joyce2013; Pérez Rodríguez and Martínez Tuñón Reference Pérez Rodríguez and Martínez Tuñón2020; Pérez Rodríguez, Martínez Tuñón, Minc, et al. Reference Pérez Rodríguez, Tuñón, Minc, Walsh and Rosales2017; Pérez Rodríguez, Martínez Tuñón, Stiver Walsh, et al. Reference Pérez Rodríguez, Tuñón, Walsh, Pérez Roldán and Estévez2017).
Monte Negro, however, did not persist into the Terminal Formative. Its abrupt abandonment remains unexplained, and where its population relocated to is not clear (Kowalewski et al. Reference Kowalewski, Balkansky, Walsh, Pluckhahn, Chamblee, Pérez Rodríguez, Espinoza and Smith2009:303–304). Unlike contemporaneous centers that adapted to political turbulence, Monte Negro and its leaders may have been unable to navigate shifting interpolity dynamics, disruptions in long-distance exchange, or local sociopolitical pressures. Its brief period of prominence underscores the inherent instability of new sociopolitical experiments in western Oaxaca, where defensive considerations, ideology, and elite strategies were closely intertwined.
Conclusion and Future Directions
Nearly a century of archaeological research in western Oaxaca confirms that Monte Negro was a central node among emerging Late Formative centers. The findings presented here continue to highlight its significance as a short-lived case study founded under unprecedented sociopolitical conditions around 300 BC. Forthcoming results promise to shed further light on Monte Negro’s internal development and broader interactions. Beyond Plaza 5, excavations in the East Sector (2023–2024) explored multiple household contexts, producing insights into domestic activities, burial practices, skeletal health, and abandonment rituals. Ongoing instrumental neutron activation analysis of over 100 pottery sherds, alongside clay samples from the Tilantongo Valley, aim to clarify the relationships between local and regional ceramic traditions and broader exchange networks. Finally, ongoing study of archaeological and ethnohistoric evidence promises to explore how Monte Negro held significance as a sacred and ancestral site within Mixtec ritual landscapes for thousands of years.
Acknowledgments
We thank Mexico’s Consejo de Arqueología and Instituto Nacional de Antropología e Historia (INAH) for research permits (401.1S.3/2023-2328; 401.1S.3-2023/87) and institutional support. We are grateful to the communities of Monte Negro and Santiago Tilantongo, including Monte Negro’s recent elected representatives Eliseo Reyes Miguel, Arturo Pedro Gutiérrez, and Taurino Hernández Cruz, as well as most recent municipal president Fortino Vicente Cruz and education secretary Magdalena Pablo Cruz. We also acknowledge team members Ana Reyes García and Leslie Cruz García, and thank Arcadio Huerta and Sergio Martínez for assistance with sample processing at LEMA. We appreciate the insightful comments of anonymous reviewers and the enduring support of Joyce Marcus, advisor to the first two authors.
Funding Statement
This research was supported by a grant from the Rust Family Foundation Archaeology Grants Program and the Wes and Shelley Cowan Graduate Fund for Scientific Analysis at the University of Michigan.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon request.
Competing Interests
The authors declare none.
Supplementary Material
For supplementary material accompanying this article, visit https://doi.org/10.1017/laq.2026.10194.
Supplementary Figure 1. The rugged Santiago Tilantongo Valley as seen from the summit of Monte Negro.
Supplementary Figure 2. La Providencia (Late Cruz Period; area based on survey by Balkansky et al. 2004) and Monte Negro (Early Ramos Period), two archaeological sites in the Santiago Tilantongo Valley.
Supplementary Figure 3. Quadrants and collection units from Glew’s 2002 intensive surface collection program at Monte Negro.
Supplementary Figure 4. Hot spots for serving bowl rim sherds are also found in the Northeast Sector, with presence noted across the rest of the site.
Supplementary Figure 5. A kernel density map for isolated axe finds reveals highest concentration in the area between the East, Northeast, and Monumental Sectors.
Supplementary Figure 6. A kernel density map for brazier isolated finds indicates a strong presence southwest of the site’s main monumental buildings, as well as in the Northeast Sector.
Supplementary Figure 7. Plaza 5 prior to excavation, with surface architecture visible.
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