The 707 area code is located in northwestern California and covers various counties and cities in the region, including Santa Rosa, Vallejo, Fairfield, Vacaville, and Napa
. It serves portions of Del Norte, Glenn, Humboldt, Lake, Marin, Mendocino, Napa, Solano, Sonoma, Tehama, and Trinity Counties
. The 707 area code is expected to be depleted of available prefixes by December 2023, and a new area code, 369, has been approved as an overlay to provide additional numbering resources for the region
. The main city covered by the 707 area code is Santa Rosa, California
