Mining can result in severe physical and chemical alterations of landscapes. Tar Creek Superfund Site, located in northeastern Oklahoma, was mined extensively for lead and zinc from the early 1900s until the 1970s and remains heavily damaged. We investigated the ecology of Red-Eared Slider Turtles (Trachemys scripta) from Beaver Creek within Tar Creek Superfund Site and two reference sites, Lake Carl Blackwell and Sequoyah National Wildlife Refuge. We measured parameters, including body size, sex ratios, sexual dimorphism indices, and recapture and survival rates. Sex ratios were female biased at Tar Creek Superfund Site and Lake Carl Blackwell and male biased at Sequoyah National Wildlife Refuge. Degree of sexual size dimorphism differed significantly among the three sites. Male T. scripta were significantly larger at Lake Carl Blackwell than at Tar Creek Superfund Site and Sequoyah National Wildlife Refuge. Females from Tar Creek Superfund Site were significantly larger than females from Lake Carl Blackwell. Survival and recapture rates did not differ significantly among the sites. Overall, we found no significant, consistent differences in population demographics of T. scripta inhabiting mined and unmined sites.