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 |
|---|---|---|---|---|---|---|
| — | 406-234 | not yet reported which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | MILES CITY | MT |
| — | 406-345 | 0XXX1XXX4XXX5XXX6XXX · 4 holders which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | GLENDIVE | MT |
| — | 406-377 | not yet reported which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | GLENDIVE | MT |
| — | 406-433 | not yet reported which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | SIDNEY | MT |
| — | 406-488 | not yet reported which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | SIDNEY | MT |
| — | 406-535 | not yet reported which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | LEWISTOWN | MT |
| — | 406-742 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 5 holders which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | FAIRVIEW | MT |
| — | 406-796 | 0XXX1XXX3XXX4XXX5XXX7XXX · 3 holders which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | WIBAUX | MT |
| — | 406-874 | none assigned yet which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | MILES CITY | MT |
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.