Over 70% of North America’s 300 freshwater mussel species are endangered, threatened, or of special concern due to threats including habitat destruction, invasive mollusc species, and climate change. The Western pearlshell mussel (Margaritifera falcata) is native to western North America and their range extends into western Wyoming, including Grand Teton National Park (GRTE). These mussels are experiencing population declines across their range including in states adjacent to Wyoming. We resurveyed 6 sites in GRTE where Western pearlshells were found during surveys in 2014. We found 1099 live mussels at 5 sites in GRTE, and the mean catch per unit effort (CPUE) was 80 mussels per person-hour compared to 109 mussels per person-hour in 2014. Overall, we observed a 31% decline in CPUE including one site where mussels were completely extirpation by a wildfire. We found three individuals <30 mm in length which appeared to be <10 years of age, suggesting successful reproduction at three sites. The observed declines of Western pearlshell in GRTE are similar to what was reported in nearby states; however, the presence of juvenile mussels provides some optimism. We recommend future monitoring of these populations to detect further declines and elucidate potential causes to enable management actions.