Bullsnakes (Pituophis catenifer sayi) have been the subject of few rigorous scientific investigations despite suspected declines. Because relatively little ecological information exists for this species, sound conservation or management decisions regarding them are difficult to make. This is particularly true in the upper Midwest, which represents the northern periphery of the snake's geographic range. Using radio-telemetry, we studied aspects of the ecology of Bullsnakes (15 males, 12 females) in Sauk County, Wisconsin, which included determining habitat preferences and movement patterns. Male and female Bullsnakes exhibited a preference for open bluff sides over habitats traditionally reported as favored by this species (i.e., sand prairies or grasslands), and avoided areas of agriculture and closed canopy bluff side forest. Nested ANOVA analysis of home ranges measured as 100% minimum convex polygons (23 ha females, 41 ha males) and 95% kernels (53 ha females, 83 ha males) were larger in males than females. Average daily movement rates were larger in males (31.7 m females, 36.7 m males). Evidence of site fidelity was also found. Based on these results, the conservation of this snake can be substantially influenced by preservation and maintenance of large sites containing open bluffs and oak savannas.