The movement of riverine animals can greatly impact the distribution of genetic variation among populations. The limited dispersal of reptiles and amphibians can produce significant genetic differentiation among geographically proximate populations. Studying the factors that contribute to genetic variation at the poleward edge of species' ranges may be particularly important as ranges shift in response to climate change. We examined physical movement and the distribution of genetic variation among populations of two riverine softshell turtle species, Apalone spinifera and Apalone mutica in Minnesota. We sequenced the mitochondrial control region and genotyped six variable microsatellite loci for 220 turtles across three river systems. Using radiotelemetry, we monitored aquatic movement and tested for sex differences in movements among 19 turtles. We found no evidence of genetic differentiation at geographic scales yielding significant differentiation in other freshwater turtles, a trend that may be attributed to high motility of Apalone turtles. The presence of dams separating several sites was not associated with genetic differentiation, likely owing to the young age of the dams relative to the generation times of Apalone. Although we found no directional gene flow toward peripheral populations, we observed the highest genetic variation in the populations closest to the range center in both species. Our findings highlight the role of physical movement on the distribution of genetic variation in riverine turtles, a relationship that may impact adaptability to climate change and other anthropogenic alterations.