Area code 831 is a telephonearea code in theNorth American Numbering Plan for a small region of theU.S. state ofCalifornia. Thenumbering plan area (NPA) comprisesMonterey County,San Benito County, andSanta Cruz County. The area code was created in 1998 in anarea code split ofarea code 408.
In 1947, theAmerican Telephone and Telegraph Company (AT&T) devised the first nationwidetelephone numbering plan and assigned theoriginal North American area codes. The state of California was divided into three numbering plan areas (NPAs) with distinct area codes:213,415, and916, for the southern, central, and northern parts of the state, respectively.[1] California area codes were reorganized geographically in 1950, so that 916 was assigned to a numbering plan area that comprised only the northeastern part from theSierra Nevada to theCentral Valley. The coastal area to the west was assignedarea code 415.[2]
Area code 408 was split from numbering plan area 415 on March 1, 1959. The new numbering plan area included most ofSanta Clara,Santa Cruz,Monterey andSan Benito Counties.
In 1997, the California/Nevada Code Administrator (C/NCA) advised theNorth American Numbering Plan Administration (NANPA) of the need for area code relief in the 408 numbering plan area. A geographicarea code split had been approved by the California Public Utilities Commission (CPUC) which would install area code 831 for a new numbering plan area comprising the communities of Santa Cruz, Salinas, Monterey, and Hollister. Area code 408 would be retained in Sunnyvale, San Jose, Los Gatos, and Gilroy. The area code split became effictive on July 11, 1998, with a permissive dialing period ending on February 20, 1999.[3]
Due to the relatively small size of the area (in both area and population), exhaustion of 831 is unlikely for the foreseeable future.[4]
The service area of NPA 831 includesBig Sur,Monterey Bay, theSalinas Valley, and the southwesternSanta Cruz Mountains.
Major cities in the area areSalinas,Hollister,Monterey,Santa Cruz and places in the northernCentral Coast.[5]
| North:408/669,650 | ||
| West:Pacific Ocean,808 | 831 | East:209/350,559 |
| South:805/820 | ||
| Hawaii area codes:808 | ||