Are all of Wyoming’s extant freshwater mussel species native to the state’s watersheds, or were they introduced by human activity? Have Wyoming’s mussel populations fluctuated in abundance throughout history, or are declines a modern issue? These and similar questions are difficult to answer in the absence of historically recorded data. Freshwater mussels are often found at archaeological sites and frequently help answer human-focused questions, but few are examined in an attempt to answer mussel-focused questions such as above. Freshwater bivalves are a diverse group that perform many ecosystem services, and over 70% of North America’s 300 freshwater mussel species are of conservation concern. Little is known about the historic distribution or population size of any of the 7 extant species of freshwater mussels in Wyoming. We reviewed and sorted thousands of shells housed at the Frision Institute at the University of Wyoming to find identifiable specimens. Shells with intact diagnostic features were identified, and growth rates, age structures, and distributions were compared to modern populations. We have thus far found 132 identifiable shells. The species we have identified were found at sites near the same watersheds where those species exist today. The presence of Western pearlshell (Margaritifera falcata) in Sweetwater and Sublette counties suggests that this species may be native to the Green River, which is a long-standing uncertainty. We have also discovered a species not known to Wyoming. Information from molluscs in archeology collections helps frame current distributions and population trends into a longer-term context to inform future management plans.