A new species of crayfish, Cambarus (Tubericambarus) stockeri, is described from northern Georgia and southern Tennessee within the Ridge and Valley Physiographic Province of North America. Of the recognized members of the subgenus, it is the most physically divergent form discovered to date. It is easily distinguished from other recognized members of the subgenus, and all other members of the genus Cambarus Erichson 1846, by the extensive tuberculation of the chelae. Cambarus (T.) stockeri has tubercles over most of the dorsal and ventral chelae surface, a character state common in members of Procambarus Ortmann, 1905b. This new species was frequently found in association with Cambarus (T.) acanthura, Hobbs, 1981 and Cambarus (Depressicambarus) cymatilis, Hobbs, 1970 and shares a close zoogeographic association with the latter species.