This report summarizes the inventory of mammals of three park units in the Southwest Alaska Network (SWAN) of the National Park Service, Alaska Region, in 2003 and 2004. This study was part of a cooperative effort of the Beringian Coevolution Project at the Museum of Southwestern Biology, University of New Mexico and the SWAN Inventory and Monitoring Program of the National Park Service of Alaska. We begin the process of documenting the approximately 38 species of mammals that occur in SWAN, with a primary focus on small mammals (i.e., shrews, voles, lemmings, weasels, porcupine, squirrels, and hares). This survey resulted in over 2000 primary specimens comprising 18 small mammal species. Small mammal captures varied considerably between [...]