what area code is 925

The area code 925 is located in California and covers the inland portions of the East Bay counties of Alameda and Contra Costa. It includes cities such as Concord, Antioch, Livermore, San Ramon, and Pleasanton. It is the only area code that serves the region. The area code was created on March 14, 1998, when area code 510 was split along the natural border of the Berkeley Hills.