Carcinization, the evolution of a crab–like morphology, has occurred in many hermit crabs. Pagurus hirsutiusculus hermit crabs exhibit geographic variation in traits associated with carcinization. Measurements derived from image analysis of P. hirsutiusculus specimens from geographic locations along the Pacific coast of North America show that Alaskan specimens: (1) are larger, (2) exhibit reduced snail shell–living, and (3) have relatively broader anterior carapaces than southern Californian specimens. This geographic variation may provide general insight into carcinization and the evolution of shell loss in hermit crabs.