Area Code 925 Information

State: CA - California
Active: True

In the North American Numbering Plan (NANP), area code 925 is an area code that covers the inland portions of the East Bay counties of Alameda and Contra Costa in central California. It was originally part of the 415 area code, 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 was created to encompass most of the Oakland 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.

Related Area Codes: 510


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