The natural history of Prairie Kingsnakes (Lampropeltis calligaster calligaster) is largely unknown because of their secretive nature. We radio-tracked 10 adult Prairie Kingsnakes (six males, four females) for one complete active season to determine activity patterns and habitat use in an area in Illinois that included forest, grassland, agricultural fields, and roads. The active season extended from approximately April to mid-October. Home ranges of males averaged over four times larger than those of females and usually included the individual's hibernation site. Males and females had similar activity levels throughout the season, with no differences in frequency of movement or distance traveled per move. Snakes were underground at least 73% of the 574 times they were relocated, suggesting most activity is nocturnal. Collectively, kingsnakes completely avoided agricultural fields and showed a preference for grasslands, but females were strongly associated with grassland edges along roads. This association with roadside edges, and failure of Prairie Kingsnakes to cross roads, suggests that roads may be barriers to movement—an observation consistent with recent evidence that roads can be barriers to movement, negatively affecting snakes in ways other than via direct mortality.