NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026
The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.
| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| 2014-10-27 | 951-523 | 0–9 XXXall 10 · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | CORONA | CA |
| 2013-10-15 | 951-435 | 0–9 XXXall 10 · 7 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | PERRIS | CA |
| 2006-01-06 | 951-770 | 0–9 XXXall 10 · 3 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | TEMECULA | CA |
| 2004-09-10 | 951-638 | 0–9 XXXall 10 · 7 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | TEMSCL CNY | CA |
| — | 951-253 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | ELSINORE | CA |
| — | 951-368 | 0XXX3XXX4XXX7XXX8XXX · 2 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | RIVERSIDE | CA |
| — | 951-375 | 0XXX1XXX2XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | TEMECULA | CA |
| — | 951-537 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | HEMT HEMT | CA |
| — | 951-565 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | WOODCREST | CA |
| — | 951-567 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | MORENO | CA |
| — | 951-665 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | HEMT SNJC | CA |
| — | 951-704 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | MURRIETA | CA |
| — | 951-723 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | SUN CITY | CA |
| — | 951-846 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | BANNING | CA |
| — | 951-893 | 0XXX1XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | CORONA | CA |
| — | 951-968 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | MIRA LOMA | CA |
| — | 951-977 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | ARLINGTON | CA |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.