We surveyed Indiana collections of freshwater gastropods from 220 museum collection lots and found 39 species inhabiting Indiana historically. Collection dates of museum material ranged from 1900 to 2006, with a median date of 1986. We collected 17,593 gastropods at 123 sites, including 86 sites where museum material was previously collected. Our surveys were combined with recent literature surveys and indicate a total of 36 species are currently present in Indiana. The Indiana fauna is composed of three species that are apparently secure globally, and 36 species that are widespread, abundant, and globally secure, including two exotics. However, three species are locally extinct and many others are locally imperiled or vulnerable. The majority of freshwater gastropod taxa in Indiana are of local conservation concern. The causes of local gastropod extinctions are unknown but likely include agricultural impacts, hydrologic alterations from reservoirs, and pollution. We recommend thorough inventory, recognition, and protection of the aquatic gastropods in Indiana.