The Southern Rocky Mountains first rose during the Laramide Orogeny (ca. 75–45 Ma), but today's mountains and adjacent Great Plains owe their current height to later epeirogenic surface uplift. When and why epeirogeny affected the region are controversial. Sedimentation histories in two central Colorado basins, the South Park–High Park and Denver basins, shifted at 56–54 Ma from an orogenic to an epeirogenic pattern, suggesting central Colorado experienced epeirogeny at that time. To interrogate that hypothesis, we analyzed thermal histories for seven samples from central Colorado's Arkansas Hills and High Park using thermochronometers with closure temperatures below ~180 °C, enabling us to track sample exhumation from ~5–7 km depth.