Area codes 510 and 341

Area codes 510 and 341 are telephone area codes in the state of California. Area code 510 was created in 1991 as a split from area code 415. It primarily serves the western part of Alameda County, including cities such as Oakland, Berkeley, Hayward, and part of Fremont, as well as parts of Contra Costa County. It was split by 925 in 1998 and then overlaid by 341 in 2019.