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 |
|---|---|---|---|---|---|---|
| 2025-04-04 | 309-971 | 1XXX which blocks → | NUSO, LLC | 732J | MONMOUTH | IL |
| 2024-11-15 | 309-961 | 1XXX9XXX · 2 holders which blocks → | NUSO, LLC | 478J | BLOOMINGTN | IL |
| 2024-10-22 | 309-730 | 0XXX1XXX8XXX9XXX · 2 holders which blocks → | NUSO, LLC | 732J | MACOMB | IL |
| 2023-03-14 | 309-930 | 1XXX6XXX8XXX9XXX · 3 holders which blocks → | NUSO, LLC | 732J | ROCKISLAND | IL |
| 2023-02-08 | 309-919 | 0XXX1XXX2XXX8XXX9XXX · 3 holders which blocks → | NUSO, LLC | 732J | PEKIN | IL |
| 2022-10-03 | 309-917 | 0XXX1XXX2XXX3XXX4XXX5XXX8XXX9XXX · 3 holders which blocks → | NUSO, LLC | 732J | PEORIA | IL |
| 2020-08-13 | 309-803 | 1XXX2XXX6XXX7XXX · 2 holders which blocks → | NUSO, LLC | 478J | CANTON | IL |
| 2013-03-13 | 309-209 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → | NUSO, LLC | 551G | MACOMB | IL |
| 2013-03-13 | 309-307 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 5 holders which blocks → | NUSO, LLC | 551G | BLOOMINGTN | IL |
| 2013-03-13 | 309-308 | 0–9 XXXall 10 · 2 holders which blocks → | NUSO, LLC | 551G | PEORIA | IL |
| — | 309-665 | 1XXX2XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | NUSO, LLC | 732J | BLOOMINGTN | IL |
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.