Lexington Hills is an unincorporated census county division (CCD) located on the eastern side of the Santa Cruz Mountains in west Santa Clara County, California. The area covers approximately , much of it open space, and contains Lake Elsman, Lexington, and Williams reservoirs, as well as the Lexington Reservoir County Park and Bear Creek Redwoods and Sierra Azul open space preserves. The Lexington Hills communities, as well as the former Almaden Air Force Station on Mount Umunhum, and Loma Prieta (highest peak in the Santa Cruz Mountains) are also located in the area.