Reservoirs represent a relatively young element of the U.S. landscape, with most reservoirs being built within the last century. Despite their recreational, ecological, and socioeconomic importance, reservoirs nationwide are suffering from severe habitat degradation. Habitat impairments related to siltation, eutrophication, poor water quality, water regime, lack of submerged structure, and macrophyte invasions affect reservoirs to differing degrees in different reservoirs. To adequately assess these issues, we needed to develop a classification system within which an assessment mechanism could function. I collected data for large reservoirs across the conterminous U.S. regarding fish habitat impairments and status of the fish community and recreational fishery. Using these data, I developed a fish habitat classification system for large U.S. reservoirs, which can be used to better understand differences among reservoirs, develop habitat management expectations, and prioritize conservation efforts.