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.
Most active assignees, all time — NPA 503
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| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| 2007-05-10 | 503-400 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | SALEM | OR |
| 2005-02-09 | 503-782 | 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | PACIFIC CY | OR |
| 2005-01-28 | 503-564 | 0XXX1XXX3XXX4XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | HOOD LAND | OR |
| 2004-04-06 | 503-483 | 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | PACIFIC CY | OR |
| 2002-09-20 | 503-354 | 0–9 XXXall 10 · 7 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | TILLAMOOK | OR |
| 2002-07-25 | 503-298 | 0–9 XXXall 10 · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | ASTORIA | OR |
| 2002-06-17 | 503-374 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | TILLAMOOK | OR |
| 2002-02-07 | 503-468 | 0–9 XXXall 10 · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | ASTORIA | OR |
| 2001-05-08 | 503-836 | 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | ASTORIA | OR |
| — | 503-339 | 4XXX5XXX6XXX7XXX · 3 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | SALEM | OR |
| — | 503-342 | 2XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | CLACKAMAS | OR |
| — | 503-343 | 0XXX1XXX2XXX4XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | CLACKAMAS | OR |
| — | 503-344 | 0XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | CLACKAMAS | OR |
| — | 503-345 | none assigned yet which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | PORTLAND | OR |
| — | 503-376 | 0XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | MCMINNVL | OR |
| — | 503-379 | not yet reported which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | MCMINNVL | OR |
| — | 503-406 | 0–9 XXXall 10 · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | CLACKAMAS | OR |
| — | 503-424 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | BEAVERTON | OR |
| — | 503-427 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | STFRD-SNDY | OR |
| — | 503-486 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | STFRD-SNDY | OR |
| — | 503-487 | 0–9 XXXall 10 · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | NEWBERG | OR |
| — | 503-523 | 3XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | BEAVERTON | OR |
| — | 503-536 | 3XXX5XXX which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | BEAVERTON | OR |
| — | 503-549 | 0XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | BEAVERTON | OR |
| — | 503-563 | 0XXX2XXX3XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | STFRD-SNDY | OR |
| — | 503-573 | 0XXX1XXX3XXX7XXX8XXX9XXX · 5 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | GRESHAM | OR |
| — | 503-713 | 1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | BEAVERTON | OR |
| — | 503-715 | 4XXX5XXX6XXX7XXX · 3 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | PORTLAND | OR |
| — | 503-822 | 0–9 XXXall 10 · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | SHERWOOD | OR |
| — | 503-828 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - OR | 3234 | BEAVERTON | OR |
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.