Area codes 415 and 628

Area codes 415 and 628 are telephone area codes in the North American Numbering Plan (NANP) for the city of San Francisco and its northern suburbs in Marin County (across the Golden Gate), and the northeast corner of San Mateo County in the U.S. state of California.

[2] In 1950, the boundaries of the numbering plan area were redrawn to produce a division of the northern and central parts along a north–south-running dividing line.

Numbering plan area 415 became the coastal region from the North Coast to the Oregon border, while 916 was redrawn to comprise the northeastern corner of the state.

[3] As part of this realignment, Sacramento was renumbered from area code 415 to 916, and Bakersfield to 213.

With the preparations for nation-wide direct distance dialing (DDD) in the early 1950s, area code 318 was temporarily used in the San Francisco area, initially by customers in Englewood, New Jersey, participating in the first customer trials to reach the city, as well as some areas north of the Golden Gate.