Area code 951 is a telephonearea code in theNorth American Numbering Plan for westernRiverside County in the southern part of theU.S. state ofCalifornia. It was assigned in 2004 to a new numbering plan area that was created by anarea code split ofarea code 909.
In 1947, when theAmerican Telephone and Telegraph Company (AT&T) devised the first nationwidetelephone numbering plan and assigned theoriginal North American area codes, the state of California was divided into three numbering plan areas: 213,415, and916, for the southern, central, and northern parts of the state, respectively.[1]The area served by 213 extended fromMexican border to theCentral Coast. Starting in the 1950s, Southern California experienced rapid expansion of telephone service, requiring area code 213 to be split five times by 1998. The first split became necessary in 1951, when most of the southern and eastern portion, includingSan Diego and most ofOrange County, was assignedarea code 714. The 714 numbering plan area was further divided on November 14, 1992, whenarea code 909 was assigned to the majority of Riverside, San Bernardino, Ontario, and Pomona.[2]
On July 17, 2004, numbering plan area 909 was divided in a two-way geographic split for assignment of area code 951 to the southern portion of 909.[3] The new numbering plan area comprised westernRiverside County, including the cities and communities ofBanning,Beaumont,Corona,Canyon Lake,Riverside,Temescal Valley,Woodcrest,Moreno Valley,Perris,Menifee,Lake Elsinore,Wildomar,Murrieta,Temecula,San Jacinto,Hemet,Lakeview,Nuevo,Norco,Eastvale,Jurupa Valley, andIdyllwild.
The creation of area code 951 is the latest area code split in California. All codes introduced in the state since have been overlays.
Prior to October 2021, area code 951 had telephone numbers assigned for thecentral office code 988. In 2020,988 was designated nationwide as a dialing code for theNational Suicide Prevention Lifeline, which created a conflict for exchanges that permitseven-digit dialing. This area code was therefore scheduled to transition toten-digit dialing by October 24, 2021.[4]
| North:909/840 | ||
| West:714/657,949 | 951 | East:760/442 |
| South:760/442 |