Kensington is an unincorporated community and census designated place located in the Berkeley Hills, in the East Bay, part of the San Francisco Bay Area, in Contra Costa County, California. In the 20th century it was considered part of Berkeley, although it is across the county line. House numbers follow the pattern used in Berkeley, and Kensington shares two zip codes with the Berkeley Hills area. The population was 5,077 at the 2010 census.