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 |
|---|---|---|---|---|---|---|
| 2002-12-30 | 435-275 | 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | ST GEORGE | UT |
| 2002-11-04 | 435-494 | 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | BRIGHAM CY | UT |
| 2002-09-18 | 435-565 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | PARK CITY | UT |
| 2002-08-21 | 435-248 | 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | TOOELE | UT |
| 2002-04-24 | 435-553 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | BRIGHAM CY | UT |
| 2002-04-24 | 435-572 | 0XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | CEDAR CITY | UT |
| 2002-04-24 | 435-612 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | MONROE | UT |
| 2002-04-24 | 435-633 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | RICHFIELD | UT |
| 2001-10-23 | 435-562 | 0–9 XXXall 10 · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | SALINA | UT |
| 2001-10-23 | 435-571 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | PARK CITY | UT |
| 2001-10-23 | 435-625 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | BEAVER | UT |
| 2001-10-23 | 435-710 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | PAROWAN | UT |
| 2001-10-23 | 435-728 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | TOOELE | UT |
| 2001-10-23 | 435-767 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | ST GEORGE | UT |
| 2001-10-23 | 435-856 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 7 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | NEPHI | UT |
| — | 435-213 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | LOGAN | UT |
| — | 435-214 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | PARK CITY | UT |
| — | 435-215 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | ST GEORGE | UT |
| — | 435-216 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | ST GEORGE | UT |
| — | 435-363 | 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | LOGAN | UT |
| — | 435-535 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | LOGAN | UT |
| — | 435-554 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | LOGAN | UT |
| — | 435-938 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | LOGAN | UT |
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.