NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/21/2026
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 |
|---|---|---|---|---|---|---|
| 2020-11-27 | 603-457 | 0–9 XXXall 10 · 4 holders which blocks → | IDT AMERICA, CORP. - NH | 314C | DOVER | NH |
| 2009-10-30 | 603-813 | 0XXX1XXX2XXX3XXX5XXX · 4 holders which blocks → | IDT AMERICA, CORP. - NH | 314C | CTRBARNSTE | NH |
| 2009-10-30 | 603-855 | 2XXX5XXX8XXX · 3 holders which blocks → | IDT AMERICA, CORP. - NH | 314C | ALTON | NH |
| 2009-10-30 | 603-872 | 2XXX which blocks → | IDT AMERICA, CORP. - NH | 314C | GLNTNIRWRS | NH |
| 2009-10-30 | 603-906 | 2XXX which blocks → | IDT AMERICA, CORP. - NH | 314C | BARNSTEAD | NH |
| 2009-10-22 | 603-701 | 1XXX2XXX · 2 holders which blocks → | IDT AMERICA, CORP. - NH | 314C | NEW DURHAM | NH |
| 2008-02-26 | 603-948 | 0–9 XXXall 10 · 7 holders which blocks → | IDT AMERICA, CORP. - NH | 314C | ROCHESTER | NH |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.