The ability to predict the effects that new or modified roads will have on species or populations of conservation interest is critically important to protection efforts. We documented patterns of movement and spatial dispersion of two sympatric snake populations by radiotracking 34 Eastern Massasaugas (Sistrurus catenatus) and 13 Eastern Hog-Nosed Snakes (Heterodon platirhinos) over four years. The two species differed substantially in their movements (frequency, rate, tortuosity, distance) and ensuing spatial dispersion. Regardless of species, males were more vagile than female conspecifics during the mating season. The primary factors hypothesized to have generated the interspecific differences in movement and spatial dispersion were foraging mode, mating system, and reproductive mode. By combining our understanding of how these snakes used space with knowledge of their natural history and ecology, we examined which attributes of their spatial ecology might render S. catenatus and H. platirhinos most susceptible to road effects. For S. catenatus, our observations suggest that spatial fidelity and space use relative to hibernacula are the primary factors influencing the species' susceptibility to road effects. For H. platirhinos, tortuous and extensive movements, space use relative to hibernacula, and large spatial dispersion distances from hibernacula are likely the most important factors.