Effective conservation requires that natural resource managers understand the diversity of organisms within a jurisdictional unit. Too frequently, conservation priorities are determined without adequate biological information, leading to inefficient use of very limited resources. We investigated molluscan community composition and richness within the eastern portion of the Sawtooth National Recreation Area (i.e., management unit) in Custer County, Idaho, USA to (1) identify populations of non-native species, if present, (2) acquire baseline information on the distribution, relative abundance, and diversity of molluscs in this high-elevation ecosystem, and (3) provide resource managers with useful information with which to inform conservation priority-setting. We found a rich molluscan community comprised of 19 species from 11 genera and 7 families. We also documented a single population of the non-native species Radix auricularia Linnaeus, 1758 from samples at Alturas Lake. Management of the very popular, eastern portion of the Sawtooth National Recreation Area should include public outreach regarding invasive species, importance of proper cleaning of boats and fishing gear, and importance of native invertebrates to healthy, functioning ecosystems.