7, 1984; split off 626 on June 14, 1997; overlaid by 747 on May 18, 2009) 820 – Overlay with 805, started service on July 2, 2018 831 – Monterey, Santa Cruz, Salinas, and Hollister; the northern Central Coast. (Split from 408 on July 11, 1998) 840 – Overlay of 909 effective February 23, 2021 858 – City of San Diego and suburbs; originally created by a split from 619 on June 12, 1999; however, re-merged with 619 to create the 619/858 overlay in June 2018 909 – San Bernardino, Ontario, Pomona, and Chino; eastern Los Angeles County and southwestern San Bernardino County. (Split from 714 on November 14, 1992; split off 951 on July 17, 2004; overlaid with 840 effective February 23, 2021.) 916 – Sacramento and most of the Sacramento metro: Folsom, Roseville; Sacramento County and southern Placer County (October 1947; overlaid with 279 on March 10, 2018) 925 – Concord, Walnut Creek, Livermore, Pleasanton, San Ramon, Martinez, and Antioch; eastern Alameda and Contra Costa Counties. (Split from 510 on March 14, 1998) 949 – Irvine, Laguna Beach, Newport Beach, San Juan Capistrano, San Clemente; southern and eastern Orange County. (Split from 714 on April 18, 1998) 951 – Riverside, Corona, Moreno Valley, Perris, Temecula, Murrieta; western Riverside County. (Split from 909 on July 17, 2004) See also List of NANP area codes North American Numbering Plan Notes Exchange boundaries do not follow city or county boundaries; many of the area codes include or exclude parts of cities or counties listed above. For example, the boundary between area codes 562 and 714 generally follows the boundary between Los Angeles and Orange Counties, but portions of Los Angeles County are in 714 and portions of Orange County are in 562. Similarly, most of Daly City is in 650, but a small portion is in 415. References External links All Area Codes in California California Area codes