Edward Gray’s Mason–Dixon: Crucible of the Nation presents a clear, intriguing account of the relationship between United States’ history and a long line of border conflict, racial conflict, and barriers between morality and inhumanity in the history of human enslavement. I assess Gray’s argument in terms of identified major premises, evaluating Mason–Dixon’s relevance to the landscape of present-day scholarship in American studies. These identified areas are the geopolitics of Baltimore in opposition to Philadelphia, the divide between slave and free states, and the final stage of the line’s conceptual role in oppressing civil rights (83). Mason–Dixon clearly examines relevance to race-based scholarship encompassing “everything to do with what the line had become: a national shame, where African American citizenship dropped away and civil rights once again became a matter of race” (372).
Gray analyses the Mason–Dixon Line as barrier and border point, examining its political implications with sustained insight and cartographic extrapolation. Mason–Dixon “tells the story of a geopolitical boundary. That boundary marked the jurisdictional and territorial limits of the colonies – which would become the states” (7). Gray’s research encompasses a turbulent period, the vestiges of which are represented only by the line’s conceptual value; geographically, there is not much that “marks one’s transit across the Line” in the modern day (7). Mason–Dixon works forwards from the conception of states and land property to long, dark periods of conflict. Moving on to the line’s establishment, Gray finishes with its role during a period enforcing enslavement through fugitive-slave barrier points, with freedom lying beyond its border. Mapping the line provides insight into borderlands conflict, retroactively mapping sectional boundaries onto peoples and citizens. Drawing the line’s boundaries enforced tariffs and fealty on marshland and forest, settled in time by farmers and tradespeople, yet remaining under the remit of nebulous state lines.
Gray’s major premise is that “the Mason–Dixon Line cut through eastern North America, its purpose to bring peace to a region racked by war. The Line never brought peace. It brought war of another kind” (6). He judiciously deploys archival research, reproducing cartographic evidence of the line, and Maryland and Pennsylvania’s pre-line landscapes. He also demarcates the line’s relevance to historical events, including its significance in the turbulent history of the United States as a series of colonies, then as a united unit, before Pennsylvania and Maryland wielded their power to limit the civil and human rights of their nonwhite populations. The line “represents the first time England attempted to confine a colony within lineal boundaries,” though border disputes were not limited to the colonizers (31).
Stymied in potential by Maryland to the north and Delaware to the east, “Pennsylvania would be bounded in space” by virtue of geography (53). The line’s status was important when resolving “civil disputes and to enforce criminal law,” in matters of early American commerce and taxation, and in fugitive punishment (16). In turn, from Lenape and Susquehannock occupancy to a land grant of the monarch, Maryland found itself “from one [colony] dominated by English indentured servants” “increasingly populated by enslaved laborers of African descent” (32–33). Pennsylvania and Maryland’s governing families frequently clashed, necessitating the arrival of astronomers Charles Mason and Jeremiah Dixon to map the west-to-east boundary.
The March 1765 Mason–Dixon expedition forged inland for 232 miles before being forced to stop “thirty-one miles short of its intended end point,” finishing in October 1767 (152). Gray examines the “political implications of a new colonial border,” and the incitation of “diplomatic crisis” in surveying “lands controlled by Delawares, Shawnees, and dissident Iroquois” (138, 150). As with much in the surrounding landscape, “it took practically no time for politics to intrude on Lord Baltimore’s fantasy” of colonial government (142). The expedition was stopped due to intervention from “a leader of the Iroquois delegation” acting on behalf of the Six Nations Council, demonstrating geopolitical disruption intruding on these states for centuries to come (152). Shown by a replicated 1768 map, Mason and Dixon’s research party records are “remarkable in … their detail, their evident accuracy, the painstaking map of geodesic findings,” yet it is clear that they were stopped short, “leaving an unmistakable void where the survey ended” in blank cartographic space where “the map’s detail ends … but Mason and Dixon carried the edges of their six-mile-wide map to the end of the paper” (161, 162).
Gray observes that “although the transformation of the regional economy gave the Line the appearance of an innocuous boundary between states, by the early nineteenth century few Americans of African descent would view the Line that way” (165). Contrasting Maryland and Pennsylvania, “by 1750, Pennsylvania [was] home to more than eight thousand slaves … in Maryland, the numbers were much higher. In 1750, more than forty thousand lived in the colony, but the vast majority remained in southern tidewater counties, where 40 to 50 percent of the population was enslaved” (170). Neither warfare “nor the Mason–Dixon Line did much to alter these demographic and economic facts” by the mid-1770s, and “the Gradual Abolition Act’s passage” in 1780 “did not abolish slavery in Pennsylvania, nor did it alter the nature of slavery in the borderlands” (171, 172). Instead, Gray mediates historical expectations, as “decades would pass before a traveler, otherwise uninformed, would have reason to conclude that in crossing the Line she crossed from a free state to a slave state” (172).
Gray’s framing pinpoints Pennsylvania’s differentiation in abolition potential. Utilizing effective comparison with Delaware and Maryland, “slaves had always represented a tiny percentage of [Pennsylvania’s] overall labor force,” and “unlike Delaware and Maryland, it was home to very few heavily invested slave owners … too few in relative numbers to constitute a substantial political threat to gradual abolition” (184). Therefore Gray notes that, compared to Delaware and Maryland, “the political economy of slavery made Pennsylvania uniquely hospitable to abolitionism” (184).
Gray also effectively counterposes Baltimore and Philadelphia as cross-line industrial juggernauts. During migration periods, Philadelphia housed “a fifth of Pennsylvania’s Black population” by 1790, also housing “less than a tenth of the state’s white population” (196). However, “although Philadelphia was America’s largest growing city until eclipsed by New York, Baltimore was the nation’s fastest-growing,” and “in 1790, almost 1,600 of the city’s 13,503 residents were Black. The vast majority of these – about 75 percent – were enslaved.” By 1790, Baltimore’s “Black population had reached more than ten thousand, and more than half were now free” (196). Gray’s analytical strength lies in data sets, though it is a weakness that he does not examine tangible people behind these population numbers.
Despite the speed of growth, by virtue of the intervening state line, “Baltimore’s Blacks, both free and slave, faced a decidedly less egalitarian and just future than did their counterparts in Philadelphia” (197). Contrasting cities synthesizes Gray’s geographic and racial analysis, as “by the 1850s, two Mason–Dixon Lines had emerged,” representing a schism of racial divide (275). Comparing these dual lines, one was “a largely innocuous jurisdictional limit with little meaning for white Americans,” yet “the other, long familiar to Black Americans, was a quasi-international border regulated by a legal apparatus” (275).
Mason–Dixon’s mediated discussion of contested borderlands demonstrates racial divides held in counteraction along the conceptual demarcation of the Mason–Dixon Line. Gray utilizes cartography and history to study the line in minute detail, providing a considered approach to US history in the line’s evolving role as racial arbiter in the mid-1800s and beyond, after initially representing the bordering states’ differing colonial points of conflict, including cross-border and cross-territory violence. Gray acutely assesses the role of invisible divides, perhaps indicative of emergent wider American behaviour. Mason–Dixon provides an important resource for scholars of both geography and history, though it is primarily an effective scholarly reference when utilized to examine America’s racial landscape, in the line’s dual function as geographic marker and elusive concept of freedom and control.
