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We investigated the impacts of the construction and operation of the Terror Lake hydroelectric project on brown bears (Ursus arctos middendorffi) on northern Kodiak Island, Alaska, during 1982-86. Radio collars were maintained on a mean of 35.6 bears throughout each year of the study. We relocated these bears an average annual total of 933.3 times during a 3-year construction period (1982-86) and 994.5 times during a 2-year post-construction period (1985-86). Bears that resided near the project used approximately the same areas each year, making only minor shifts to areas with dense cover during construction. In areas near the project, bears used alpine habitat less, and midslope and lowland habitat more than expected, based on availability. Over 90% of the bear locations in alpine habitat near the project were made after construction activities ceased, suggesting that bears avoided these open areas during construction. Dense, brushy cover in midslope and lowland habitats gave bears secure cover, so they continued to use preferred feeding areas near the project both during and after construction. Areas of mean home range polygons for 5 females closely asociated, and 8 females unassociated, with the project were not significantly different (P > 0.1) during construction and post-construction periods. Individual bears varied widely in their relative associations with the project, but several bears were commonly located near active construction. Impacts on denning were less than predicted because most bears denned in areas remote from and at elevations above project features. Bears exhibited high fidelity to the same denning areas irrespective of the bears' association with project features. Total habitat lost to inundation and removal of vegetation was <0.5% of the study area. Improved vehicular and foot access provided by constructed roads and powerlines, and the increased incentive for development of rural lands provided by surplus electric power, is expected to have longterm impacts on bears through increased disturbance and killing of bears by recreationists and settlers. Mitigation of the project included dedication of adjacent lands for wildlife and creation of a trust fund to support research and habitat maintenance for bears.