Area code 510

Area code 510 is a California telephone area code that was split from area code 415 on September 2, 1991. It covers most eastern Bay Area cities in Alameda County (including the city of Oakland but excluding Dublin, Livermore, Pleasanton, and Sunol), and western Contra Costa County. Area code 925 was created on March 14, 1998 from the eastern portion of the then 510 area code. The East Bay Hills serve as the rough dividing line.

Area code 510

Area code 510 is a California telephone area code that was split from area code 415 on September 2, 1991. It covers most eastern Bay Area cities in Alameda County (including the city of Oakland but excluding Dublin, Livermore, Pleasanton, and Sunol), and western Contra Costa County. Area code 925 was created on March 14, 1998 from the eastern portion of the then 510 area code. The East Bay Hills serve as the rough dividing line.