The object of this study was to identify types of freshwater sponges present in western Montana and to determine destribution of the different species. An attempt was also made to estimate growth rate. In Salmon Lake, Ephydatia muelleri. and Spongilla lacustris were found. In Blanchard Lake, Ephvdataia muelleri. Sponailla lacustris. and Eunapius fragilis were identified. Within Rock Island Lake, Eunapius fragilis and Ephydatia fluviatilis (tentative) were identified.