Gomphurus septima was known in Alabama only from specimens collected in Tuscaloosa County in the 1930s and 1940s, and the species was long believed to be extirpated from the state. In 2002, a population was discovered along the Little Cahaba River in Bibb County; a second population, also in Bibb County, was found at the Cahaba River in 2006. These populations represent the southern and western limits of the overall range of the species; the nearest known populations occur in the Carolinas. The preferred habitat is medium to large rocky rivers.