The Mammal Collection of the Illinois Natural History Survey at the University of Illinois was established in 1876. The INHS Mammal Collection is housed in rooms 142 and 144 of the Natural Resources Studies Annex. As of April 2024 the Mammal Collection had over 30,000 lots of specimens, from over 39,000 individuals, with over 58,000 preparations. This ranks as one of the 35 largest mammal collections in the world based on the number of specimens. The specimens are used for scientific studies, primarily when loaned to scientists at other institutions, but are also used as comparative material to identify specimens brought to the Illinois Natural History Survey and for teaching classes at the University of Illinois.

Our goal is to acquire a broad spatial and temporal representation of populations of mammals from Illinois, with a secondary emphasis on mammals from North America and elsewhere across the Earth. Specimens are acquired as the result of collecting trips, exchanges, salvaging, donations, purchases, and permanent loans. We attempt to archive multiple datasets and modes of preservation in an effort to stimulate the maximum number of scientific and educational studies that can be conducted on each voucher specimen. Typically, traditional methods of preservation (skin, skeleton) are used, as well as newer methods, including tissue and hair samples and photo vouchers. We also archive well-documented voucher specimens prepared in the course of non-systematic investigations, especially those conducted by state and federal resource agencies.