Alamosa County is located in the middle of the San Luis Valley (the Valley) of south central Colorado. The county seat, the City of Alamosa, is located in the middle of the county, and is the largest city in the San Luis Valley. The Town of Hooper’s jurisdictional boundaries are located within both Alamosa and Saguache Counties; however, the greatest population areas within the Town of Hooper are within Alamosa County. The City of Alamosa and the Town of Hooper are the only incorporated municipalities in Alamosa County. Alamosa East is a census-designated place covering 3.6 square miles of unincorporated land. Mosca is an unincorporated town with a post office.