Eclogites offer unique insights into geodynamics and crust–mantle evolution as they record processes occurring deep in subduction zones. Those hosted in continental crust are more likely to be exhumed and preserve records of the metamorphic peak. However, the thermal regime of subducted continental crust is understudied. The Western Gneiss Region (WGR) is a giant continental (ultra)high-pressure terrain formed during the collision of Baltica and Laurentia. We investigated the pressure–temperature (P-T) paths of several WGR eclogites on the regional scale to evaluate the thermal evolution of the subducted slab. A combined approach applying garnet–clinopyroxene–phengite with quartz-in-garnet, Zr-in-rutile and Ti-in-quartz thermobarometry, yielding a consistent P-T dataset across the WGR. Prograde conditions varied between 1.08 ± 0.16 GPa, 627 ± 31°C, and 1.78 ± 0.18 GPa, 639 ± 30°C, whereas the peak conditions rose from 2.69 ± 0.32 GPa at 643 ± 30°C in the south up to 5.40 GPa (–2.45, + 1.40) at 840 ± 30°C in the north. Our results reveal a gradient of 4.7°C/km, typical of a cold subduction regime, and consistent with models of subduction systems exceeding 2 GPa, but they show higher temperatures than models for lower pressures. The discrepancy with the spatial gradient at outcrop may suggest tectonic shortening. Our data highlight similarities in the P-T evolutions of continental and oceanic crust in the deepest parts of subduction. Continental crust exhumed from a subduction zone can then be regarded as a proxy to investigate processes occurring in subduction and collisional systems.