A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for longnose dace (Rhinichthys cataractae), a freshwater fish. The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for freshwater, marine and estuarine areas of the continental United States. Habitat suitability indexes (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service.