Area code 805 was created in 1957, when one of the
original North American area codes in California, 213, was reduced in size to provide more central office codes in the Los Angeles area. In 1998, the California-Nevada Code Administration (CNCA) determined that California was under "substantial number growth" which required exhaustion mitigation in the 805 numbering plan area, by splitting the eastern part of the NPA into a new plan area with the
area code 661. The split was effective on February 13, 1999, for the
San Joaquin Valley,
Santa Clarita Valley, and
Antelope Valley. In August 2016, the
California Public Utilities Commission held a series of hearings for the decision of providing a relief area code in NPA 805 in the form of an
overlay or an
area code split. On May 25, 2017, the Commission approved 820 as an overlay area code. New telephone numbers of 820 area code began service in June 2018, requiring
ten-digit dialing for all calls. In addition to the municipalities below, area code 805 also serves the US military facilities in
Kwajalein,
Republic of the Marshall Islands with a
Paso Robles prefix (805-355). This arrangement originated from the
US Army's first satellite communications station having been built at nearby
Camp Roberts. ==Service area==