In the North American Numbering Plan

North American Numbering Plan

The North American Numbering Plan is an integrated telephone numbering plan administered by Neustar which encompasses 24 countries and territories, including the United States and its territories, Canada, Bermuda, and 16 nations of the Caribbean...

 (NANP), area code 925 is an area code that covers the inland portions of the East Bay counties of Alameda

Alameda County, California

Alameda County is a county in the U.S. state of California. It occupies most of the East Bay region of the San Francisco Bay Area. As of the 2010 census it had a population of 1,510,271, making it the 7th most populous county in the state...

 and Contra Costa

Contra Costa County, California

Contra Costa County is a primarily suburban county in the San Francisco Bay Area of the U.S. state of California. As of the 2010 census, it had a population of 1,049,025...

 in northern California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

.

It was originally part of the 415 area code

Area code 415

North American Area code 415 is the Californian telephone area code for San Francisco and its northern suburbs .-History:415 was one of the original three area codes in California, established in 1947...

, one of the first three area codes created in California in 1947, which originally covered all of central California. In 1991 the 510

Area code 510

North American area code 510 is a California telephone area code which covers most eastern Bay Area cities in Alameda County , and western Contra Costa County...

 area code was created to encompass most of the Oakland

Oakland, California

Oakland is a major West Coast port city on San Francisco Bay in the U.S. state of California. It is the eighth-largest city in the state with a 2010 population of 390,724...

 Metropolitan Statistical Area (MSA). The 925 area code was created March 14, 1998, when the 510 area code was itself split along the natural border of the East Bay Hills. The number was formed by taking 415 and adding 510 which equals 925. It currently includes most of Contra Costa County and the eastern portion of Alameda County and is wholly contained within the Oakland MSA.

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).

Alameda County

Alameda County, California

Alameda County is a county in the U.S. state of California. It occupies most of the East Bay region of the San Francisco Bay Area. As of the 2010 census it had a population of 1,510,271, making it the 7th most populous county in the state...

• Dublin
  Dublin, California
  Dublin is a suburban city of the East Bay region of Alameda County, California, United States. Located along the north side of Interstate 580 at the intersection with Interstate 680, roughly east of Hayward, west of Livermore and north of San Jose, it was named after the city of Dublin in...
  
  
• Kilkare Woods
  Kilkare Woods, California
  Kilkare Woods is a small rural unincorporated community of about 773 people in southern Alameda County, California, near Pleasanton. The town is along Kilkare Road and is in zip code 94586. It lies at an elevation of 827 feet . 96% of residents of the zip code spoke English as their primary...
  
  
• Livermore
  Livermore, California
  Livermore is a city in Alameda County. The population as of 2010 was 80,968. Livermore is located on the eastern edge of California's San Francisco Bay Area....
  
  
• Pleasanton
  Pleasanton, California
  Pleasanton is a city in Alameda County, California, incorporated in 1894. It is a suburb in the San Francisco Bay Area located about east of Oakland, and west of Livermore. The population was 70,285 at the 2010 census. In 2005 and 2007, Pleasanton was ranked the wealthiest middle-sized city in...
  
  
• Sunol
  Sunol, California
  Sunol is an unincorporated census-designated place in Alameda County, California, United States. The population was 913 at the 2010 census....
  
  

Contra Costa County

Contra Costa County, California

Contra Costa County is a primarily suburban county in the San Francisco Bay Area of the U.S. state of California. As of the 2010 census, it had a population of 1,049,025...

• Alamo Oaks
  Alamo Oaks, California
  Alamo Oaks is an unincorporated community in Contra Costa County, California, United States. It is located in the hills near Alamo in the San Ramon Valley. It lies at an elevation of 515 feet . The ZIP Code is 94507. The community is inside area code 925....
  
  
• Alamo
  Alamo, California
  Alamo is an unincorporated community and census-designated place in Contra Costa County, California, in the United States. It is located in the East Bay region of the San Francisco Bay Area...
  
  
• Antioch
  Antioch, California
  Antioch is a city in Contra Costa County, California. Located in the East Bay region of the San Francisco Bay Area along the San Joaquin-Sacramento River Delta, it is a suburb of San Francisco and Oakland. The city's population was 102,372 at the U.S...
  
  
• Bay Point
  Bay Point, California
  Bay Point, formerly West Pittsburg, is a suburb and census-designated place located in eastern Contra Costa County, California, just west of the city of Pittsburg and northeast over a low range of hills from Concord...
  
  
• Bethel Island
  Bethel Island, California
  Bethel Island is a census-designated place on Bethel Island in Contra Costa County, California, United States. The population was 2,137 at the 2010 census.-Geography:...
  
  
• Blackhawk
  Blackhawk, California
  Blackhawk is an unincorporated master planned community and census-designated place located in Contra Costa County, California, east of Danville and Oakland. The ZIP Code is 94506. The community is inside area code 925.-Blackhawk Ranch, 1917 to 1979:...
  
  
• Blackhawk-Camino Tassajara
• Brentwood
  Brentwood, California
  Brentwood is a city in Contra Costa County, California, United States. It is located in the East Bay region of the San Francisco Bay Area. The population is 51,481 as of 2010....
  
  
• Byron
  Byron, California
  Byron is a census-designated place in Contra Costa County, California, United States. The population was 1,277 at the 2010 census.-Geography:...
  
  
• Christie
  Christie, California
  Christie is an unincorporated community in Contra Costa County, California, United States. It is on the Atchison, Topeka and Santa Fe Railroad east-southeast of Martinez, at an elevation of 292 feet . It is located in the hills between Hercules and Martinez, accessible via State Route 4. The ZIP...
  
  
• Clayton
  Clayton, California
  Clayton is a city in Contra Costa County, California, United States. The population was 10,897 as of the 2010 census.- Geography :...
  
  
• Clyde
  Clyde, California
  Clyde is a census-designated place in Contra Costa County, California, United States. The population was 678 at the 2010 census. It is located east of Martinez.-Geography:...
  
  
• Concord
  Concord, California
  Concord is the largest city in Contra Costa County, California, USA. At the 2010 census, the city had a population of 122,067. Originally founded in 1869 as the community of Todos Santos by Salvio Pacheco, the name was changed to Concord within months...
  
  
• Danville
  Danville, California
  The Town of Danville is located in the San Ramon Valley in Contra Costa County, California. It is one of the incorporated municipalities in California that uses "town" in its name instead of "city". The population was 42,039 in 2010. Danville is one of the wealthiest suburbs of Oakland and San...
  
  
• Diablo
  Diablo, California
  Diablo is a census-designated place in Contra Costa County, California, United States. The population was 1,158 at the 2010 census. It is located east-northeast of Danville...
  
  
• Discovery Bay
  Discovery Bay, California
  Discovery Bay is a census-designated place in extreme eastern Contra Costa County, California in the United States about from San Francisco. As of 2010, its population was 13,352....
  
  
• Knightsen
  Knightsen, California
  Knightsen is a census-designated place in Contra Costa County, California, in the United States. As of the 2010 census, the CDP population was 1,568, up from 861 reported in the 2000 census.-Geography:...
  
  
• Lafayette
  Lafayette, California
  Lafayette is a city in Contra Costa County, California, United States. As of the 2010 census, the city's population was 23,893. It was named after the Marquis de Lafayette, a French military hero of the American Revolutionary War...
  
  
• Marsh Creek Springs
  Marsh Creek Springs, California
  Marsh Creek Springs is an unincorporated community in Contra Costa County, California. It lies at an elevation of 584 feet . It consists of approximately 2 by 8 blocks along Marsh Creek Road southeast of Clayton. The town is named for Marsh Creek, a local stream. The ZIP Code is 94517. The...
  
  
• Martinez
  Martinez, California
  Martinez is a city and the county seat of Contra Costa County, California, United States. The population was 35,824 at the 2010 census. The downtown is notable for its large number of preserved old buildings...
  
  
• Moraga
  Moraga, California
  Moraga is a suburban incorporated town located in Contra Costa County, California, United States, in the San Francisco Bay Area. It is named in honor of Joaquin Moraga, whose grandfather was José Joaquin Moraga, second in command to Juan Bautista de Anza...
  
  
• Oakley
  Oakley, California
  Oakley is a city in Contra Costa County, California, United States. The population was 35,432 at the 2010 U.S. Census. Oakley is part of the East Contra Costa Bicycle Plan, which has existing facilities in Oakley as well as plans for further expansion....
  
  
• Orinda
  Orinda, California
  -2010:The 2010 United States Census reported that Orinda had a population of 17,643. The population density was 1,389.5 people per square mile . The racial makeup of Orinda was 14,533 White, 149 African American, 22 Native American, 2,016 Asian, 24 Pacific Islander, 122 from other races, and...
  
  
• Orwood
  Orwood, California
  Orwood is an unincorporated community in Contra Costa County, California, United States. It is located on the Atchison, Topeka and Santa Fe Railroad east of Brentwood, at an elevation of 3 feet . The ZIP Code is 94514. The community is inside area code 925.A post office operated at Orwood from...
  
  
• Pacheco
• Pittsburg
  Pittsburg, California
  Pittsburg is a city located in eastern Contra Costa County, California, the outer portion of the East Bay region of the San Francisco Bay Area. The population was 63,264 at the 2010 census....
  
  
• Pleasant Hill
  Pleasant Hill, California
  Pleasant Hill is a city in Contra Costa County, California, United States, in the East Bay of the San Francisco Bay Area. The population was 33,152 at the 2010 census. It was incorporated in 1961...
  
  
• Rock City
  Rock City, California
  Rock City is a camping & hiking zone in Contra Costa County, California, United States. It lies at an elevation of 1545 feet . The ZIP Code is 94528. The community is inside area code 925....
  
  
• San Ramon
  San Ramon, California
  -2010 census:The 2010 United States Census reported that San Ramon had a population of 72,148. The population density was 3,991.1 people per square mile...
  
  
• Saranap
  Saranap, California
  Saranap is a residential census-designated place within central Contra Costa County, California. Lying at an elevation of 180 feet , it is bounded on the south and east by portions of Walnut Creek and on the north and west by Lafayette...
  
  
• Shore Acres
  Shore Acres, California
  Shore Acres is a suburban unincorporated area in eastern Contra Costa County, California, in the San Francisco Bay Area adjacent to Bay Point and the Concord Naval Weapons Station. Bus service is provided by Tri-Delta Transit and connects the community with job centers in Concord and BART in Bay...
  
  
• Sparkle
  Sparkle, California
  Sparkle is an unincorporated community in Contra Costa County, California, United States. It is on the former route of the Sacramento Northern Railroad, now replaced by elevated BART tracks north of downtown Walnut Creek, at an elevation of 85 feet...
  
  
• Waldon
  Waldon, California
  Waldon is a former census-designated place in Contra Costa County, California, United States. The population was 5,133 at the 2000 census. The Pittsburg/Bay Point – SFO Line line of the Bay Area Rapid Transit system serves the surrounding area using the Pleasant Hill/Contra Costa Centre Station...
  
  
• Walnut Creek
  Walnut Creek, California
  Walnut Creek is an incorporated city located east of the city of Oakland. It lies in the East Bay region of the San Francisco Bay Area. While not as large as neighboring Concord, Walnut Creek serves as the business and entertainment hub for the neighboring cities within central Contra Costa...
  
  
• Walnut Heights
  Walnut Heights, California
  Walnut Heights is an unincorporated community in Contra Costa County, California, United States. It is located in the hills near Walnut Creek, at an elevation of 200 feet . The ZIP Code is 94595. The community is inside area code 925....
  
  
• Werner
  Werner, California
  Werner is an unincorporated community in Contra Costa County, California, United States. It is located on the Atchison, Topeka and Santa Fe Railroad east of Brentwood, at an elevation of 3 feet . The ZIP Code is 94514. The community is inside area code 925....
  
  

External links

• Report on the 925 area code produced by the California Public Utilities Commission
  California Public Utilities Commission
  The California Public Utilities Commission is a regulatory agency which regulates privately owned public utilities in the state of California, including electric power, telecommunications, natural gas and water companies...
  
  , Telecommunications Division
• List of exchanges from AreaCodeDownload.com, 925 Area Code