Fissidens hyalinus Hook. & Wils. is often considered to be one of the rarest mosses in the United States. The species, however, is much more common than has previously been assumed. Sixty-five new collections of F. hyalinus, in combination with previous collections, document the species from 28 counties, 7 states, and 5 major physiographic provinces. The species is newly reported for Alabama, Tennessee, and Virginia. Fissidens hyalinus is most frequent on bare soil of streambanks in steep and deeply dissected landscapes with calcareous geology and mixed deciduous forests.