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 406
New assignments by month
Sep 2026
Aug 2026
Jul 2026
Jun 2026
May 2026
Apr 2026
Mar 2026
Feb 2026
Jan 2026
Dec 2025
Nov 2025
Oct 2025
| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| — | 406-635 | 0XXX1XXX2XXX3XXX6XXX7XXX8XXX · 5 holders which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | TERRY | MT |
| — | 406-636 | not yet reported which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | LAVINA | MT |
| — | 406-637 | 3XXX4XXX6XXX7XXX8XXX · 3 holders which blocks → | QWEST CORPORATION | 9636 | TERRY | MT |
| — | 406-638 | 0XXX1XXX5XXX6XXX8XXX · 4 holders which blocks → | PROJECT TEL. CO., INC. | 2250 | HARDIN | MT |
| — | 406-639 | not yet reported which blocks → | PROJECT TEL. CO., INC. | 2250 | LODGEGRASS | MT |
| — | 406-640 | 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | WYELLOWSTN | MT |
| — | 406-641 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | WYELLOWSTN | MT |
| — | 406-642 | 0XXX4XXX5XXX7XXX8XXX · 2 holders which blocks → | QWEST CORPORATION | 9636 | VICTOR | MT |
| — | 406-644 | 0XXX1XXX4XXX · 2 holders which blocks → | BLACKFOOT TEL. COOP., INC. | 2235 | CHARLO | MT |
| — | 406-645 | 2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | ONVOY, LLC - MT | 453F | DEER LODGE | MT |
| — | 406-646 | 2XXX3XXX6XXX8XXX · 3 holders which blocks → | QWEST CORPORATION | 9636 | WYELLOWSTN | MT |
| — | 406-648 | none assigned yet which blocks → | NEMONT TEL COOP INC | 2247 | NOHINSDALE | MT |
| — | 406-649 | 0XXX1XXX which blocks → | BLACKFOOT TEL. COOP., INC. | 2235 | ST REGIS | MT |
| — | 406-650 | not yet reported which blocks → | SAGEBRUSH CELLULAR, INC. | 443B | WOLF POINT | MT |
| — | 406-651 | 7XXX which blocks → | QWEST CORPORATION | 9636 | BILLINGS | MT |
| — | 406-652 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BILLINGS | MT |
| — | 406-653 | none assigned yet which blocks → | NEMONT TEL COOP INC | 2247 | WOLF POINT | MT |
| — | 406-654 | 9XXX which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 3310 | MALTA | MT |
| — | 406-655 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BILLINGS | MT |
| — | 406-656 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BILLINGS | MT |
| — | 406-657 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BILLINGS | MT |
| — | 406-658 | not yet reported which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 2257 | SOUTHMALTA | MT |
| — | 406-659 | 5XXX6XXX7XXX8XXX · 4 holders which blocks → | QWEST CORPORATION | 9636 | NO PARKMAN | MT |
| — | 406-660 | 3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC | 6010 | DILLON | MT |
| — | 406-661 | 0XXX4XXX6XXX8XXX which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | BILLINGS | MT |
| — | 406-662 | 0XXX1XXX2XXX4XXX6XXX7XXX8XXX · 5 holders which blocks → | QWEST CORPORATION | 9636 | BRIDGER | MT |
| — | 406-663 | not yet reported which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 2257 | RAPELJE | MT |
| — | 406-664 | not yet reported which blocks → | PROJECT TEL. CO., INC. | 2250 | BELFRY | MT |
| — | 406-665 | 0XXX which blocks → | QWEST CORPORATION | 9636 | HARDIN | MT |
| — | 406-666 | not yet reported which blocks → | PROJECT TEL. CO., INC. | 2250 | FORT SMITH | MT |
| — | 406-667 | not yet reported which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 2257 | BROADVIEW | MT |
| — | 406-668 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX · 5 holders which blocks → | QWEST CORPORATION | 9636 | FROMBERG | MT |
| — | 406-669 | not yet reported which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 2257 | MOLT | MT |
| — | 406-670 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | BILLINGS | MT |
| — | 406-671 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | BILLINGS | MT |
| — | 406-672 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | BILLINGS | MT |
| — | 406-673 | none assigned yet which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 2257 | HAYS | MT |
| — | 406-674 | none assigned yet which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 2257 | WHITEWATER | MT |
| — | 406-675 | not yet reported which blocks → | RONAN TEL. CO. | 2252 | PABLO | MT |
| — | 406-676 | not yet reported which blocks → | RONAN TEL. CO. | 2252 | RONAN | MT |
| — | 406-677 | 0XXX1XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → | BLACKFOOT TEL. COOP., INC. | 2235 | SEELEYLAKE | MT |
| — | 406-678 | not yet reported which blocks → | BLACKFOOT TEL. COOP., INC. | 2235 | HAUGAN | MT |
| — | 406-679 | 4XXX7XXX · 2 holders which blocks → | NUSO, LLC | 732J | HARDIN | MT |
| — | 406-681 | not yet reported which blocks → | SOUTHERN MONTANA TEL. CO. | 2254 | GRANT | MT |
| — | 406-682 | 0XXX which blocks → | 3 RIVERS TEL. COOP., INC. | 2255 | ENNIS | MT |
| — | 406-683 | not yet reported which blocks → | QWEST CORPORATION | 9636 | DILLON | MT |
| — | 406-684 | not yet reported which blocks → | 3 RIVERS TEL. COOP., INC. | 2255 | TWINBRIDGS | MT |
| — | 406-685 | not yet reported which blocks → | 3 RIVERS TEL. COOP., INC. | 2255 | HARRISON | MT |
| — | 406-686 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → | QWEST CORPORATION | 9636 | CLYDE PARK | MT |
| — | 406-687 | 0XXX2XXX4XXX which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | W GLENDIVE | MT |
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.