In the western United States, American badgers (Taxidea taxus) excavate large volumes of soil and create fan-shaped mounds while foraging for fossorial rodents. Densities of 790 mounds/ha were recorded on the Snake River Plain, west-central Idaho. More mounds were recorded from unburned compared with burned sites, but no differences were found between sites dominated by sagebrush (Artemisia tridentata wyomingensis) and winterfat (Krascheninnikovia lanata). Mounds and diggings occupied an average of 5–8% of the landscape and the mass of mounded soil averaged 33.8 kg, equivalent to 26 t/ha. The surface cover of plants, cryptogams, and litter increased, and bare ground decreased, as mounds aged. Excavation holes were present at 96% of active and crusted mounds compared with 31% of older recovering mounds. Sites with a greater density of shrubs tended to have a greater density of both badger mounds and ground squirrel diggings. Additionally, increased density of badger mounds was associated with increases in the density of ground squirrel holes and scratchings. These results indicate that badger mounds are a significant landscape structure and that badger activity is likely to have major impacts on soil and ecosystem processes in shrub–steppe ecosystems.