Area codes 510 and 341 are telephone area codes in the North American Numbering Plan (NANP) serving much of the East Bay in the U.S. state of California. They cover parts of Contra Costa County and western Alameda County, including the city of Oakland, but excluding Dublin, Livermore, Pleasanton, and Sunol.
Area code 510 was established on September 2, 1991, in a split from area code 415. [1] On March 4, 1998, the inland portion of the East Bay was split off as area code 925. The dividing line followed the Berkeley Hills; almost everything west of the hills stayed in 510, while everything east of the hills transferred to 925.
In response to projections that 510 would exhaust in the second quarter of 2019, the California Public Utilities Commission approved the addition of an overlay area code, 341, to serve the East Bay. The first central office codes in 341 became available on July 22, 2019. [2] [3] Ten-digit dialing became mandatory in the East Bay a month earlier, on June 22. [4]
The service area contains the following cities in two counties.
By 2016, the California Public Utilities Commission (CUPC) projected that NPA 510 would exhaust its numbering pool by the second quarter of 2019. In response, the commission held meetings in Berkeley, Oakland and Hayward in January and February 2017 to discuss area code relief for 510. [2] The North American Numbering Plan Administrator (NANPA) proposed in May 2017 that CPUC relieve 510 by introducing the overlay area code 341 for the entire territory. NANPA had previously assigned 341 as the relief area code for 510 in 1999, but nationwide number pooling procedures eliminated the need at that time. The NANPA retained 341 for the then-future relief of 510. [5] CPUC accepted the NANPA proposal in a decision on June 21, 2018. [3] With the start of the overlay plan in July 2019, all customers in the numbering plan area can be assigned telephone numbers with either code, and must dial the area code for all calls; otherwise, a recorded message will remind them if they dial incorrectly. [6] [7]
In 1962, AT&T assigned NPA 510 for conversion to dial service of the Teletypewriter Exchange Service (TWX) in the United States. [8] [9] Telex use of area code 510 was decommissioned in 1981 after conversion of the service to new transmission technologies by Western Union,
Area codes 213 and 323 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of California. They are assigned in an overlay complex to a numbering plan area (NPA) that comprises, roughly, the area of central Los Angeles, including several Southeast LA communities, such as Bell and Huntington Park. Area code 213 was one of the original North American area codes of 1947 and 323 was created in an area code split of 213 in 1998. This was the fifth split of 213 and left it serving only downtown Los Angeles and immediately adjoining neighborhoods. In 2017, the two NPAs were recombined in the overlay.
Area codes 415 and 628 are telephone area codes in the North American Numbering Plan (NANP) for the city of San Francisco and its northern suburbs in Marin County, and the northeast corner of San Mateo County in the U.S. state of California. Area code 415 was one of the eighty-six original North American area codes established in 1947, but modified in geographic configuration later. Area code 628 was assigned in 2015 to form an overlay in that numbering plan area in mitigation of central office prefix exhaustion.
Area codes 805 and 820 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of California. The numbering plan area (NPA) includes most or all of the counties of San Luis Obispo, Santa Barbara, Ventura, and the southernmost portions of Monterey County. 805 was split from area code 213 in 1957, and area code 820 was added to the NPA in 2018, creating an area code overlay.
Ten-digit dialing is a telephone dialing procedure in the countries and territories that are members of the North American Numbering Plan (NANP). It is the practice of including the area code of a telephone number when dialing to initiate a telephone call. When necessary, the ten-digit number may be prefixed with the trunk code 1, which is referred to as 1+10-digit dialing or national format.
Area codes 920 and 274 are telephone area codes in the North American Numbering Plan (NANP) for a large area of eastern Wisconsin. Area code 920 was created on July 26, 1997, in a split of area code 414, one of the original North American area codes of 1947. 274 was added to the same numbering plan area (NPA) on May 5, 2023 to create an area code overlay.
Area codes 310 and 424 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of California. The numbering plan area includes the West Los Angeles and South Bay areas of Los Angeles County, a small portion of Ventura County, and Santa Catalina Island, which is located 26 miles (42 km) south.
Area codes 909 and 840 are telephone area codes in the North American Numbering Plan for the far-eastern part of Los Angeles County and southwestern San Bernardino County in the U.S. state of California. Area code 909 was created on November 14, 1992 in an area code split of 714, and 840 was added to the numbering plan area to form an overlay complex effective February 23, 2021.
Area codes 876 and 658 are telephone area codes in the North American Numbering Plan (NANP) for Jamaica.
Area codes 910 and 472 are telephone area codes in the North American Numbering Plan (NANP) for southeastern North Carolina. The area codes form an overlay for a numbering plan area (NPA) that includes the cities of Wilmington, Jacksonville, Laurinburg, Lumberton and Fayetteville. Area code 910 was established in 1993, and 472 was added to the same area in October 2022.
Area code 925 is a telephone area code in the North American Numbering Plan for a northern part of the U.S. state of California. It was created in an area code split of area code 510 in 1998. The numbering plan area comprises the inland portions of the East Bay counties of Alameda and Contra Costa.
Area code 530 is a telephone area code in the North American Numbering Plan (NANP) in northeastern and Northern California. It was created in 1997 in an area code split of 916.
Area codes 707 and 369 are telephone area codes in the North American Numbering Plan (NANP) for the northwestern part of the U.S. state of California. The area codes serve part of the northern San Francisco Bay Area, as well as the North Coast. Major cities in the area codes include Napa, Sebastopol, Vallejo, Benicia, Fairfield, Santa Rosa, Windsor, Healdsburg, Rohnert Park, Petaluma, Fort Bragg, Rio Vista, Crescent City, Eureka, Clearlake, Vacaville, Dixon, and Ukiah. 707 was created by a split of area code 415 on March 1, 1959. Area code 369 was added to the numbering plan area (NPA) on February 1, 2023, to form an overlay numbering plan in the service area.
Area codes 610, 484, and 835 are telephone area codes in the North American Numbering Plan (NANP) for the eastern and southeastern regions of Pennsylvania. The numbering plan area (NPA) includes regions to the west of Philadelphia and the cities Allentown, Bethlehem, and Reading. It includes much of the Delaware Valley, including almost all of Delaware County, most of the Philadelphia Main Line, and all of the Lehigh Valley.
Area codes 215, 267, and 445 are telephone area codes in the North American Numbering Plan (NANP) for Philadelphia and adjacent portions of Bucks and Montgomery counties in the U.S. state of Pennsylvania. Area code 215 was one of the original North American area codes established in 1947, while 267 and 445 are overlay codes for the same numbering plan area (NPA).
Area code 318 is a telephone area code in the North American Numbering Plan (NANP) for the northern and central parts of the U.S. state of Louisiana.
Area code 810 is a telephone area code in the North American Numbering Plan for the east-central part in the U.S. state of Michigan. The numbering plan area (NPA) comprises the cities of Flint, Lapeer, Port Huron, and the southern portion of the Thumb.
Area codes 513 and 283 are telephone area codes in the North American Numbering Plan (NANP) for the southwest of the U.S. state of Ohio, including Cincinnati and surrounding cities, such as Forest Park, Hamilton, Lebanon, West Chester, Mason, Maineville, Middletown, Milford, Norwood, Oxford, Harrison, Cleves, Miamitown and Trenton.
Area codes 818 and 747 are telephone area codes in the North American Numbering Plan (NANP) for the San Fernando Valley region of Los Angeles County in the U.S. state of California.
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: CS1 maint: archived copy as title (link)North: 707 | ||
West: 415/628, 650 | area code 510/341 | East: 925 |
South: 408/669 |