Area Code Atlas

NANP- Split of 909 Numbering Plan Area (NPA) with 951 NPA and subsequent Overlay of 909 Numbering Plan Area (NPA) with 752 NPA - California

909/951 NPA Split Suspended Temporarily (California)

Planned split of 909 to create 951 (cancelled)

A planned split of area code 909 to create 951 for western Riverside County was scheduled for September 9, 2000, but was cancelled due to number conservation measures and public opposition.

CPUC approved split of 909 to create 951

The California Public Utilities Commission approved a two-way geographic split of area code 909 on November 13, 2003. The northern region would retain 909, while the southern portion would become area code 951.

909 NPA; 2-way Split, Creating 951 NPA California

NPA 951 split from 909

Area code 951 was created on July 17, 2004, when western Riverside County was split off from area code 909. This split was part of the relief plan originally scheduled in 2000, with some residents in Eastvale and Corona allowed to retain the 909 area code. Area code 752 was returned to the numbering pool and was not used.

Permissive dialing begins for 951 split from 909

Permissive dialing for the new area code 951 began on July 17, 2004, following the split of area code 909. During this period, calls could be completed using either the old or new area code.

CA 909/951 NPA Split-Reminder Planning Letter

Mandatory dialing for 951 and 909 after split

Mandatory dialing of the new area code 951 began on October 30, 2004, ending the permissive period. Callers were required to use the correct area code for numbers in the new 951 region.

Ten-digit dialing becomes mandatory in 951 in Western Riverside County, California due to 988

Ten-digit dialing became mandatory in area code 951 in Western Riverside County, California, on October 24, 2021, to resolve conflicts with the 988 central office code, which was designated for the National Suicide Prevention Lifeline. This change was part of the nationwide implementation of 988 as the three-digit code for the Lifeline, aimed at eliminating conflicts with existing dialing patterns.