We examined current distributions of and influential variables on aquatic gastropods in streams and springs across the state. Our research located 37 species representing 7 families. This inventory included rare species such as Somatogyrus pennsylvanicus Walker, 1904 and several populations of the Ohio Pebblesnail Somatogyrus integra (Say, 1829). Despite targeted surveys, no collections were made of the Buffalo Pebblesnail Gillia altilis (I. Lea, 1841). We also examined the influence of rapid bio-assessment habitat measurements, reach and basin hydrological variables, and selected water chemistry variables on the freshwater snail communities of Pennsylvania. Several measures of habitat quality, drainage area, and water chemistry were among the more important variables explaining patterns in species richness. Several species appear rare and 7 species are recommended for conservation consideration. Further work is needed to better understand the diversity of freshwater gastropods in Pennsylvania.