NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026
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 |
|---|---|---|---|---|---|---|
| 2007-07-03 | 858-246 | 0–9 XXXall 10 · 2 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | LA JOLLA | CA |
| — | 858-240 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | RNCHOPNQTS | CA |
| — | 858-309 | 2XXX4XXX5XXX8XXX · 3 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | SNDG LVTA | CA |
| — | 858-332 | 1XXX2XXX · 2 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | LA JOLLA | CA |
| — | 858-357 | 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | SNDG MRMS | CA |
| — | 858-380 | 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | SNDG LVTA | CA |
| — | 858-386 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | POWAY | CA |
| — | 858-480 | 1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | DEL MAR | CA |
| — | 858-617 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | DEL MAR | CA |
| — | 858-649 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 8 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | RNCHOBRNDO | CA |
| — | 858-651 | not yet reported which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | LA JOLLA | CA |
| — | 858-736 | 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | LA JOLLA | CA |
| — | 858-746 | 0XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | POWAY | CA |
| — | 858-754 | 1XXX2XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | LA JOLLA | CA |
| — | 858-779 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | RNCHOSANFE | CA |
| — | 858-798 | 1XXX2XXX3XXX4XXX5XXX6XXX9XXX · 6 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | RNCHOBRNDO | CA |
| — | 858-805 | 1XXX2XXX3XXX4XXX5XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | SNDG MRMS | CA |
| — | 858-845 | not yet reported which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | LA JOLLA | CA |
| — | 858-882 | 7XXX which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | LA JOLLA | CA |
| — | 858-943 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | LEVEL 3 TELECOM OF CALIFORNIA, LP - CA | 7718 | RNCHOBRNDO | CA |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.