ABSTRACT Archaeology of a Late Prehistoric Ethnic Frontier, Naknek River, Alaska This project examines the territorial limit of late prehistoric people of Alutiiq (southernmost Eskimo) speech along the lower Naknek River in southwestern Alaska, specifically at a point on or near the frontier of encounter with another group of people at the end of the eighteenth century. The territory of this Alutiiq people (dating from about A.D. 1450 to 1800) is expected to be marked by a distinctive house form, common elsewhere only on the Kodiak Island group, and by particular artifacts. Excavations at a relatively undisturbed site on the lower river will help to shed light on the late prehistoric territorial limits and the length of time that two separate communities coexisted in the region.