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 54 square miles (140 km2), 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.
As of the 2010 US Census, the population was 4,009 residents of whom 83.2% were non-Hispanic white, 8.4% Hispanic, 4.0% Asian, and 4.4% of other races, with a median age of 45.0 years old.
Most residents and businesses in the area use postal zip codes from neighboring cities of Almaden, Lexington Hills, and Los Gatos. The telephone area code is 408.
The region lies on the eastern side of the Santa Cruz Mountains, and supports a relatively cool Mediterranean climate.