Area code 707

Area code 707 is a telephone area code in the North American Numbering Plan (NANP) for the northwestern part of the U.S. state of California. It was created by a split of numbering plan area 916 on March 1, 1959. It serves part of the northern San Francisco Bay Area, as well as the North Coast. Major cities in the area code include Napa, Sebastopol, Vallejo, Benicia, Fairfield, Santa Rosa, Windsor, Healdsburg, Rohnert Park, Petaluma, Fort Bragg, Crescent City, Eureka, Clearlake, Vacaville, Ukiah, and northwestern California. In addition, when area code 916 split into area code 530 on November 1, 1997, the Dixon area moved from area code 916 to 707 and also from the Sacramento local access and transport area (LATA) into the San Francisco LATA.

Map of California numbering plan areas (blue) and border states. Area code 707 is shown in red.

When area code 707 was activated, it became California's eighth area code (along with 213, 415, 916, 714, 408, 805, and 209), and the last new area code in the state until 619 was added in 1982. It is not only the only one of these area codes never to have required relief, but it is also the only one of California's thirteen "original format" area codes (i.e., area codes with a "0" or "1" as their middle digit, the others being 310, 510, 818 and 909, all of which, in addition to 619, were introduced decades after 707's debut) not to require relief from a "new format" area code (those with 2–8 as their middle digit, which were introduced beginning in 1995 when the NANP ran out of the original format NPAs), despite explosive growth in the area, particularly its southern portion, as well as the proliferation of cell phones and pagers. As of 1Q 2020, 707 is not projected to need area code relief until at least mid-2025. (In 1999, a three-way, two-phase split of the 707 area code was scheduled such that a new 627 area code would serve most of Napa and Sonoma Counties as well as small portions of Marin and Mendocino Counties while a new 369 area code would serve Solano County as well as a small portion as Napa County beginning in December of 2000 and October of 2001, respectively. However, due to number pooling, the California Public Utilities Commission cancelled both of these splits on July 27, 2000.) As of 2018, area code 707 has been forecast to exhaust in the latter half of 2025.[1]