Area code 831

458/541775702928442/760916/279530707209559831805661858909951619213323707916/279415650510/341925408209831805661442/760310/424747/818626909951949562657/714
Numbering plan areas in California (blue) and border states. This map is clickable; click on any region shown to visit the page for those area codes.Area code 831 is shown in red.

Area code 831 is a telephone area code in the North American Numbering Plan for a small region of the U.S. state of California. The numbering plan area (NPA) comprises Monterey County, San Benito County, and Santa Cruz County. The area code was created in 1998 in an area code split of area code 408.