Area Code Atlas

Area code 415 established as an original area code

In 1947, area code 415 was established as one of the original North American area codes, initially covering central California including San Francisco and extending from Sacramento to Bakersfield.

California NPA boundaries redrawn

In 1950, the boundaries of California's numbering plan areas were redrawn, shifting 415 to the coastal region from the North Coast to the Oregon border, reassigning Sacramento to 916 and Bakersfield to 213, and realigning the boundary between NPAs 213 and 415 northward to include Bakersfield in 213.

California NPA boundaries redrawn, including 415 and 916

In 1950, the boundaries of California's numbering plan areas were redrawn. Area code 415 was reassigned to the coastal region from the North Coast to the Oregon border, while area code 916 was remapped to cover northeastern California, including the Sierra Nevada to the Central Valley. Sacramento was reassigned from 415 to 916 as part of this statewide realignment.

First Direct Distance Dialing call using NPA 201

On November 10, 1951, the first customer-dialed long-distance call was made from Englewood, New Jersey (area code 201) to Alameda, California (area code 415), marking the introduction of Direct Distance Dialing.

NPA 415 split to create NPA 707 in 1959

In 1959, area code 415 was split to create NPA 707 for northern California regions, including the northern coast, as part of a three-way split from 415, which also included the creation of area code 408 for San Jose and the South Bay.

NPA 408 split from 415 in 1959

In 1959, area code 408 was created from the southern part of 415, covering San Jose, the South Bay, Monterey Bay, and Salinas Valley. The split from 415 was part of the same 1959 division, but the existing record correctly attributes the creation of 408 separately from the 707 split.

NPA 408 split from 415

On March 1, 1959, area code 408 was created in a flash-cut split from area code 415. The new 408 area code covered most of Santa Clara, Santa Cruz, Monterey, and San Benito Counties, while 415 continued to serve the San Francisco Bay Area.

NANP - REVISED DATE FOR SPLIT OF 415 (CALIFORNIA) NUMBERING PLAN AREA

NPA 510 split from 415

Area code 510 was created in 1991 as a split from 415 to serve most of the East Bay region of California, including cities such as Oakland and Berkeley.

NPA 510 split from 415 for the East Bay in 1991

On September 2, 1991, area code 510 was created for the East Bay, including Oakland, splitting from area code 415 to address growing demand for telephone numbers in the region. 415 continued to serve San Francisco and Marin County.

NANP-Split of 415 (California) Numbering Plan Area (NPA)

Extraordinary NPA-Specific Conservation Procedures for 310, 415, 619 and 714 NPAs (California)

Changes to the 415 and 714 NPA (California) Relief Plans

NPA 650 split from 415 for San Mateo County in 1997

Area code 650 was created on August 2, 1997, as a geographic split from area code 415, covering most of San Mateo County, parts of San Francisco, and the northwestern Santa Clara County, including Palo Alto and Mountain View.

NANP- Overlay of 415 Numbering Plan Area (NPA) with 628 NPA - California

Suspension of overlay relief for 408 and other NPAs

On December 16, 1999, the California Public Utilities Commission suspended the implementation of planned overlays for area codes 408, 415, 510, 650, 714, and 909. This action was taken due to the adoption of telephone number pooling, which delayed the need for additional area codes.

Overlays Suspended in the 408, 415, 510, 650, 714 & 909 NPAs

NPA 415, 619, 650, 707 - Relief Plans Dismissed (California)

NPA 628 overlay on 415 announced

NPA 628 to Overlay NPA 415 (California)

Area code 628 overlaid on 415 in 2015

Area code 628 was added as an overlay to the 415 numbering plan area on February 21, 2015, to address the exhaustion of available central office prefixes. The overlay required ten-digit dialing for all calls within the region, covering San Francisco, Marin County, and northeast San Mateo County, California.

Mandatory ten-digit dialing implemented for 415/628 overlay

Ten-digit dialing became mandatory in the 415 and 628 area codes on February 21, 2015, following the introduction of the 628 overlay to ensure sufficient numbering resources.

Overlay planned for 415 with new code 628

Area code 628 was assigned in 2015 to overlay the 415 numbering plan area to mitigate central office prefix exhaustion. This change required ten-digit dialing with prefix 1 from landlines.