What is what area code is 628?

Area code 628 is a telephone area code in California that was introduced as an overlay for area code 415. It serves the same geographic area as 415, which includes most of the City%20and%20County%20of%20San%20Francisco and Marin County, as well as small portions of San Mateo County. This means that in this region, ten-digit dialing is required for all calls. The need for the overlay was due to the exhaustion of available phone numbers in the original 415 area code. It went into service in 2015.