The topography of an area affects the animals that live in at. Using digitized topographic maps of our mountainous study area in North Carolina. USA, and using radio telemetry data for locations of black bears Ursus americanus, we tested the hypotheses that topography influences home ranges of black bears and that topography affects access to resources by black bears. Use of space by bears correlated positively with steepness of slope but negatively with relative elevation. The perimeters of bears” home ranges aligned with ridges and valleys more than expected by chance and home ranges were oriented on major topographic features, such as watersheds and basins. Bears’ homo ranges had lower resource values than was optimal for their home range locations and access to resources was limited by topography'. Ignoring topography may lead researchers to misunderstand the ecology and behavior of animals that live in mountainous areas.