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 |
|---|---|---|---|---|---|---|
| 2017-10-03 | 858-302 | 0–9 XXXall 10 · 7 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | SNDG LVTA | CA |
| — | 858-256 | 0–9 XXXall 10 · 6 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | SNDG LVTA | CA |
| — | 858-285 | 0–9 XXXall 10 · 6 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | SNDG LVTA | CA |
| — | 858-296 | 0–9 XXXwhole prefix which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | SNDG LVTA | CA |
| — | 858-299 | 0–9 XXXall 10 · 4 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | DEL MAR | CA |
| — | 858-303 | 0–9 XXXwhole prefix which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | LA JOLLA | CA |
| — | 858-312 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | RNCHOBRNDO | CA |
| — | 858-345 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | DEL MAR | CA |
| — | 858-371 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | RNCHOPNQTS | CA |
| — | 858-397 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | SNDG MRMS | CA |
| — | 858-634 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | SNDG LVTA | CA |
| — | 858-768 | 0–9 XXXall 10 · 6 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | LA JOLLA | CA |
| — | 858-832 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | RNCHOSANFE | CA |
| — | 858-842 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | COMCAST PHONE OF CALIFORNIA, LLC | 394L | POWAY | 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.