A survey of the mammals at Hidden Springs State Forest (HSSF) in Shelby County, Illinois was conducted from May 1 to November 18, 1984. The survey was designed to determine the species and relative abundance of mammals associated with major habitat types of the Forest based on area walk-through surveys, streamside surveys, mist net surveys, snaptrap/pitfall surveys, and a hunter questionaire. A total of 26 mammal species were found associated with various habitats within the Forest and an additional four species were reported within Shelby County. One species, the southeastern shrew (Sorex longirostris) had not previously been reported in Shelby County. Within HSSF the large deciduous and edge habitats had the highest mammal diversities. Of the areas trapped for small mammals edge and conifer plantation habitats had the highest abundance of mammals taken in snap-traps and pitfalls. Habitat associations for each mammal species found at HSSF were defined. Mammals not found on the Forest but whose known range includes Shelby County are discussed
