Area code 925 is a

telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...

area code A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, rea ...

that was split from

area code 510 Area is the quantity that expresses the extent of a region on the plane or on a curved surface. The area of a plane region or ''plane area'' refers to the area of a shape or planar lamina, while '' surface area'' refers to the area of an open s ...

in the U.S. state of

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, on March 14, 1998. It covers the inland portions of the East Bay counties of

Alameda An alameda is a Avenue (landscape), street or path lined with trees () and may refer to: Places Canada *Alameda, Saskatchewan, town in Saskatchewan **Grant Devine Dam, formerly ''Alameda Dam'', a dam and reservoir in southern Saskatchewan Chile ...

and Contra Costa in the northern area of California. The area was originally part of

area code 415 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 (across the Golden Gate), and the northeast corner of San Mateo County in the U.S. ...

, one of the first three area codes created in California in 1947, which originally covered all of central California. In 1991,

was created to encompass most of the

East Bay The East Bay is the eastern region of the San Francisco Bay Area and includes cities along the eastern shores of the San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa countie ...

. Area code 925 was created March 14, 1998, when area code 510 was split along the natural border of the

Berkeley Hills The Berkeley Hills are a range of the Pacific Coast Ranges that overlook the northeast side of the valley that encompasses San Francisco Bay. They were previously called the "Contra Costa Range/Hills" (from the original Spanish ''Sierra de la C ...

. The area code includes southeastern Alameda County (Dublin, Pleasanton, Livermore, Sunol, and unincorporated areas surrounding those communities), and all of Contra Costa County except the western part (El Cerrito to Crockett). Prior to October 2021, area code 925 had telephone numbers assigned for the

central office code The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the international calling ...

988. In 2020, ''988'' was designated nationwide as a dialing code for the

National Suicide Prevention Lifeline The 988 Suicide & Crisis Lifeline (formerly known as the National Suicide Prevention Lifeline) is a United States-based suicide prevention Suicide prevention is a collection of efforts to reduce the risk of suicide. Suicide is often preven ...

, which created a conflict for exchanges that permit

seven-digit dialing Seven-digit dialing is a telephone dialing procedure customary in some territories of the North American Numbering Plan (NANP) for dialing telephone numbers in the same numbering plan area (NPA). NANP telephone numbers consist of ten digits, of wh ...

. The area code was therefore transitioned to

ten-digit dialing 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 telep ...

on October 24, 2021.

Cities in the 925 area code

Alameda County

* Altamont * Dougherty *

Dublin Dublin (; , or ) is the capital and largest city of Republic of Ireland, Ireland. On a bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, bordered on the south by the Dublin Mountains, a part of th ...

* East Pleasanton * Kilkare Woods * Livermore * Pleasanton * San Ramon Village * Sunol * Ulmar

Contra Costa County

Alamo The Battle of the Alamo (February 23 – March 6, 1836) was a pivotal event in the Texas Revolution. Following a 13-day siege, Mexican troops under President General Antonio López de Santa Anna reclaimed the Alamo Mission near San Ant ...

* Alamo Oaks *

Antioch Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ� ...

* Bay Point * Bethel Island * Bixler *

Blackhawk Black Hawk and Blackhawk may refer to: Animals * Black Hawk (horse), a Morgan horse that lived from 1833 to 1856 * Common black hawk, ''Buteogallus anthracinus'' * Cuban black hawk, ''Buteogallus gundlachii'' * Great black hawk, ''Buteogallus uru ...

Blackhawk-Camino Tassajara Blackhawk-Camino Tassajara is a former census-designated place (CDP) in Contra Costa County, California, near the town of Danville. The unincorporated area consisted of the Blackhawk planned community and the surrounding Camino Tassajara area. A ...

* Brentwood *

Byron George Gordon Byron, 6th Baron Byron (22 January 1788 – 19 April 1824), known simply as Lord Byron, was an English romantic poet and Peerage of the United Kingdom, peer. He was one of the leading figures of the Romantic movement, and h ...

Canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...

* Clayton *

Clyde Clyde may refer to: People * Clyde (given name) * Clyde (surname) Places For townships see also Clyde Township Australia * Clyde, New South Wales * Clyde, Victoria * Clyde River, New South Wales Canada * Clyde, Alberta * Clyde, Ontario, a tow ...

Concord Concord may refer to: Meaning "agreement" * Pact or treaty, frequently between nations (indicating a condition of harmony) * Harmony, in music * Agreement (linguistics), a change in the form of a word depending on grammatical features of other ...

* Danville * Diablo *

Discovery Bay Discovery Bay (DB) is a resort town on Lantau Island, Hong Kong. It consists of mixed, primarily residential, development, in particular upmarket residential development and private and public recreational facilities, including garden houses, ...

* Knightsen *

Lafayette Lafayette or La Fayette may refer to: People * Lafayette (name), a list of people with the surname Lafayette or La Fayette or the given name Lafayette * House of La Fayette, a French noble family ** Gilbert du Motier, Marquis de Lafayette (1757� ...

* Marsh Creek Springs * Martinez * Mococo *

Moraga Moraga is a List of municipalities in California, town in Contra Costa County, California, Contra Costa County, California, in the San Francisco Bay Area. The town is named in honor of Joaquín Moraga, member of the famed Californio family. As ...

* Norris Canyon * Oakley * Orinda * Orwood *

Pacheco Pacheco is a Portuguese and Spanish name which may refer to: General * Alex Pacheco (born 1958), animal rights activist, co-founder of PETA. *Ángel Pacheco (general) (1793-1869), was an Argentine military officer trained by José de San Martín ...

* Pittsburg * Pleasant Hill * San Ramon * Saranap * Shore Acres * Vine Hill * Waldon *

Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...

References

External links

Report on the 925 area code
produced by the

California Public Utilities Commission The California Public Utilities Commission (CPUC or PUC) is a regulatory agency that regulates privately owned public utilities in the state of California, including electric power, telecommunications, natural gas and water companies. In additi ...

, Telecommunications Division
List of exchanges from AreaCodeDownload.com, 925 Area Code
{{coord, 37.9, -122, region:US-CA, display=title 925 Alameda County, California Contra Costa County, California 925 Northern California

Cities in the 925 area code

Alameda County

Contra Costa County

See also

References

External links