show Abstracthide AbstractIn this study, we investigated the population genomic structure of western populations of the widespread painted turtle (Chrysemys picta) to assess genomic evidence of local adaptation and past demography. We wanted to understand the potential role of local adaptation, as assessed through reduced representation sequencing, in the colonization and persistence of populations of painted turtles in the middle and western United States. Populations in this region were previously hypothesized to be the result of a rapid expansion of painted turtles westward following glacier recession and were reported to have few genetic differences among them. We tested this hypothesis and the hypothesis that local adaptation allows populations to survive in the differing environments sampled, and the results inform our understanding of evolutionary patterns in this long-lived, widespread ectotherm that is vulnerable to future climatic conditions.