951
Area code
Statusin service
Introduced2004-07-17
JurisdictionCA, US
Local dialing1+10D
Time zonePacific
Last verified2026-09-17
Utilization 89.5% of assignable prefixes assigned
As of 09/17/2026
0%709 of ~792 assignable NXX values (200–999 excl. N11)100%
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-01-26, most recent 2026-09-14.
Area codes serve rate-center geographies, not municipal boundaries. “CA” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | T-MOBILE USA, INC. | 120 | 16.9% |
| 02 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | 99 | 14% |
| 03 | NEW CINGULAR WIRELESS PCS, LLC | 76 | 10.7% |
| 04 | PACIFIC BELL | 75 | 10.6% |
| 05 | FRONTIER CALIFORNIA INC. | 69 | 9.7% |
| 06 | ONVOY, LLC - CA | 47 | 6.6% |
| 07 | BANDWIDTH.COM CLEC, LLC - CA | 32 | 4.5% |
| 08 | LEVEL 3 COMMUNICATIONS, LLC - CA | 26 | 3.7% |
| 09 | METROPCS NETWORKS, LLC | 24 | 3.4% |
| 10 | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 17 | 2.4% |
Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.
Change history
Recorded events for this NPA- 2004-07-17Area code 951 entered service (created from 909).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2021-01-08 | PL-556 ↗ | Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Lifeline) – supersedes PL-544 |
| 2020-08-17 | PL-544 ↗ | Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline |
| 2003-12-12 | PL-334 ↗ | 909 NPA; 2-way Split, Creating 951 NPA California |
| 2000-02-24 | PL-215 ↗ | 909/951 NPA Split Suspended Temporarily (California) |
| 2000-01-14 | PL-206 ↗ | Overlays Suspended in the 408, 415, 510, 650, 714 & 909 NPAs |
| 1999-08-26 | PL-189 ↗ | NANP- Split of 909 Numbering Plan Area (NPA) with 951 NPA and subsequent Overlay of 909 Numbering Plan Area (NPA) with 752 NPA - California |