831 Area Code is part of 3 counties in the state of California. There are around 18 cities and 44 other places such as towns, cdps and villages in the 831 area code. Area code 831 is a telephone area code in the North American Numbering Plan (NANP) for the U.S. state of California. Below you will find more info about Code and also zip codes, counties, cities and the post offices that belong to this Area Code.
Sources: North American Numbering Plan Administration (NANPA), telecom providers, and the U.S. Census Bureau.