Area codes 415 and 628
415 was one of the original three area codes in California, established in 1947. It originally covered central California, south of area code 916 and north of area code 213. It stretched from Sacramento in the north to Bakersfield in the south. 
In 1950, 415 was expanded along the North Coast to the Oregon border and shortened in the south, while 916 was rotated to cover the northeastern corner of the state.  As part of this realignment, Sacramento was shifted from 415 to 916, while Bakersfield moved to 213.
For a short time in the early 1950s, area code 318 was temporarily used, initially by customers in Englewood, New Jersey, participating in the first customer direct distance dialing experiment to reach San Francisco as well as some areas north of the Golden Gate.  In 1953, the entire Bay Area was "reunited" in using area code 415.
Area 415 has been split three times due to the Bay Area's rapid expansion:
- On March 1, 1959, area code 408 was created for San Jose and the South Bay.  (408 has since been split to 831 and overlaid with 669.)
- On September 2, 1991, area code 510 was created for the East Bay, including Oakland.  (510 has since been split to 925 and will be overlaid by 341 in 2019.)
- On August 2, 1997, area code 650 was created; the partition approximately followed the boundary between San Francisco, which (along with Marin County) kept 415, and San Mateo County to the south, which received the new code. Deviations from the county line included a very small area east of the San Francisco Golf Club, which was changed to 650,  and portions of Brisbane and Daly City, which remained in 415. 
On February 21, 2015, area code 628 was assigned as an overlay for new numbers in the 415 territory, making ten-digit dialing mandatory in the area, with eleven-digit dialing necessary from landlines.  Until then, 415 had been one of the few urban area codes not to be overlaid, making San Francisco one of the largest cities where seven-digit dialing was still possible.
- Bel Marin Keys
- Black Point-Green Point
- California Park
- Corte Madera
- Inverness Park
- Lagunitas-Forest Knolls
- Lucas Valley-Marinwood
- Marin City
- McNears Beach
- Mill Valley
- Muir Beach
- Paradise Cay
- Point Reyes Station
- San Anselmo
- San Geronimo
- San Quentin
- San Rafael
- Santa Venetia
- Sleepy Hollow
- Stinson Beach
- Tamalpais-Homestead Valley
- "Archived copy". Archived from the original on 2015-02-26. Retrieved 2015-02-25.CS1 maint: archived copy as title ( link)
- Madison, Linc (1999-05-27). "LincMad's 1947 Area Code Map". Archived from the original on 4 January 2007. Retrieved 2007-01-06.
- Moore, Carl (1996-02-12). "history.of.area.splits". TELECOM digest. Retrieved 2007-01-06.
- Cuccia, Mark (1996-08-13). "Re: When Was Direct Distance Dialing Cut In?". TELECOM digest. Retrieved 2007-01-06.
- Madison, Linc. "NANP Area Code History: 1948 - 1959". Archived from the original on 2002-09-11. Retrieved 2007-01-06.
- Fabisch, M.P. (1990-06-13). "NANPA Revised Date for Split of 415 (California) Numbering Plan Area" (PDF). Bellcore Letter. Retrieved 2007-01-06.
- "AT&T- News Room". Att.com. 1998-01-28. Retrieved 2012-09-07.
- Deak, J.N. (1996-11-22). "NANPA Revised Date for Split of 415 (California) Numbering Plan Area" (PDF). North American Numbering Plan Letter. PL-NANP-022. Retrieved 2007-01-06.
- Rubenstein, Steve (2015-02-20). "415, meet 628: New S.F. area code debuts Saturday". SFGate. Retrieved 2020-04-26.
|California area codes: 209, 213/323, 279/916, 310/424, 341/510, 408/669, 415/628, 442/760, 530, 559, 562, 619/858, 626, 650, 657/714, 661, 707, 747/818, 805/820, 831, 840/909, 925, 949, 951|
|West: Pacific Ocean, 808||area code 415/628||East: 510/341, 925|
|Hawaii area codes: 808|