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 |
|---|---|---|---|---|---|---|
| 2021-07-22 | 858-323 | 0–9 XXXall 10 · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | CHULAVISTA | CA |
| 2018-06-07 | 858-258 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | SNDG MRMS | CA |
| 2014-10-01 | 858-257 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | LA JOLLA | CA |
| 2014-04-22 | 858-281 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | LA JOLLA | CA |
| 2013-03-29 | 858-465 | 0–9 XXXall 10 · 8 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | DEL MAR | CA |
| 2006-01-06 | 858-461 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | DEL MAR | CA |
| 2005-12-19 | 858-952 | 0–9 XXXall 10 · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | LA JOLLA | CA |
| — | 858-201 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | SNDG MRMS | CA |
| — | 858-346 | 3XXX which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | LA JOLLA | CA |
| — | 858-375 | 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | POWAY | CA |
| — | 858-429 | 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | SNDG LVTA | CA |
| — | 858-762 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | POWAY | CA |
| — | 858-834 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | RNCHOPNQTS | CA |
| — | 858-863 | 2XXX3XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | SNDG MRMS | CA |
| — | 858-876 | 2XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | DEL MAR | CA |
| — | 858-914 | 0–9 XXXall 10 · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | RNCHOSANFE | CA |
| — | 858-925 | 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | DEL MAR | CA |
| — | 858-951 | 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | RNCHOSANFE | 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.