A new crayfish, Orconectes (Gremicambarus) quinebaugensis, is described from southern New England. This species is similar in morphology to its sister species, O. (G.) virilis (Hagen), which also occurs in New England. Orconectes quinebaugensis is found in small streams with rocky or gravel substrate, with or without O. virilis or other crayfish species. Orconectes quinebaugensis differs from other members of the O. virilis species complex in the morphology of the first pleopods of adult males; in O. quinebaugensis, both rami of the first pleopod are clearly and equally recurved, and the central projection comprises 30.2–34.0% of the total length of the pleopod. In addition, it can be distinguished from all known members of the complex by the shape of the dactyl of the chelipeds.