Bonner-West Riverside (Salish: Nʔaycčstm, "Place of the Big Bull Trout" ) is a census-designated place (CDP) in Missoula County, Montana, United States, including the unincorporated communities of Bonner, Milltown (formerly Riverside), West Riverside, and Pinegrove. It is part of the Missoula metropolitan area. The population was 1,690 at the 2020 census.