NumberResearchRecent prefix assignments
334 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/28/2026
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, last 30 days
New assignments by month
Sep 2026
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Dec 2025
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Oct 2025
| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| — | 406-533 | 4XXX5XXX8XXX9XXX · 2 holders which blocks → | QWEST CORPORATION | 9636 | BUTTE | MT |
| — | 406-534 | 0–9 XXXall 10 · 4 holders which blocks → | CHARTER IP ENABLED SERVICES, LLC | 792K | BILLINGS | MT |
| — | 406-535 | not yet reported which blocks → | MID-RIVERS TELEPHONE COOPERATIVE, INC. | 7830 | LEWISTOWN | MT |
| — | 406-537 | not yet reported which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 2257 | MELVILLE | MT |
| — | 406-538 | none assigned yet which blocks → | QWEST CORPORATION | 9636 | LEWISTOWN | MT |
| — | 406-539 | not yet reported which blocks → | NEW CINGULAR WIRELESS PCS, LLC | 6010 | BOZEMAN | MT |
| — | 406-540 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | ONVOY, LLC - MT | 453F | MISSOULA | MT |
| — | 406-541 | not yet reported which blocks → | BLACKFOOT COMMUNICATIONS, INC. - MT | 7870 | MISSOULA | MT |
| — | 406-542 | not yet reported which blocks → | QWEST CORPORATION | 9636 | MISSOULA | MT |
| — | 406-543 | not yet reported which blocks → | QWEST CORPORATION | 9636 | MISSOULA | MT |
| — | 406-544 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | MISSOULA | MT |
| — | 406-546 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | MISSOULA | MT |
| — | 406-547 | none assigned yet which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 3310 | WHSLPHRSPG | MT |
| — | 406-548 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | QWEST CORPORATION | 9636 | BOZEMAN | MT |
| — | 406-549 | not yet reported which blocks → | QWEST CORPORATION | 9636 | MISSOULA | MT |
| — | 406-550 | 4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | NUSO, LLC | 732J | MISSOULA | MT |
| — | 406-553 | 1XXX3XXX which blocks → | NEW CINGULAR WIRELESS PCS, LLC | 6010 | DIVIDE | MT |
| — | 406-554 | not yet reported which blocks → | RANGE TEL COOP INC | 2251 | NO BROADUS | MT |
| — | 406-555 | not yet reported which blocks → | MULTIPLE OCN LISTING | MULT | DIR ASST | MT |
| — | 406-556 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BOZEMAN | MT |
| — | 406-557 | 1XXX3XXX7XXX · 3 holders which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | JORDAN | MT |
| — | 406-559 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | ANACONDA | MT |
| — | 406-560 | 9XXX which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | ANACONDA | MT |
| — | 406-562 | not yet reported which blocks → | 3 RIVERS TEL. COOP., INC. | 2255 | AUGUSTA | MT |
| — | 406-563 | 0XXX which blocks → | QWEST CORPORATION | 9636 | ANACONDA | MT |
| — | 406-566 | 7XXX which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 3310 | STANFORD | MT |
| — | 406-567 | not yet reported which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 3310 | DENTON | MT |
| — | 406-568 | 4XXX which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | RYEGATE | MT |
| — | 406-569 | not yet reported which blocks → | RESERVATION TEL. COOP. | 1632 | WSQUAW GAP | MT |
| — | 406-570 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | BOZEMAN | MT |
| — | 406-571 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | CHARTER IP ENABLED SERVICES, LLC | 792K | FINLEY PT | MT |
| — | 406-572 | not yet reported which blocks → | TRIANGLE TEL. COOP. ASSN., INC. | 3310 | MARTINSDL | MT |
| — | 406-573 | 0XXX1XXX6XXX8XXX · 3 holders which blocks → | SIYEH COMMUNICATIONS | 619J | BROWNING | MT |
| — | 406-574 | 0XXX2XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | QWEST CORPORATION | 9636 | SILVERTIP | MT |
| — | 406-575 | not yet reported which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | NO RYEGATE | MT |
| — | 406-576 | 1XXX7XXX9XXX · 3 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC | 6010 | CONRAD | MT |
| — | 406-577 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | ONVOY, LLC - MT | 453F | BOZEMAN | MT |
| — | 406-578 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → | QWEST CORPORATION | 9636 | WILSALL | MT |
| — | 406-579 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | BOZEMAN | MT |
| — | 406-580 | not yet reported which blocks → | NEW CINGULAR WIRELESS PCS, LLC | 6010 | BOZEMAN | MT |
| — | 406-581 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | BOZEMAN | MT |
| — | 406-582 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BOZEMAN | MT |
| — | 406-583 | not yet reported which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | BLOOMFIELD | MT |
| — | 406-584 | none assigned yet which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | LINDSAY | MT |
| — | 406-585 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BOZEMAN | MT |
| — | 406-586 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BOZEMAN | MT |
| — | 406-587 | not yet reported which blocks → | QWEST CORPORATION | 9636 | BOZEMAN | MT |
| — | 406-588 | not yet reported which blocks → | MID-RIVERS TEL. COOP., INC. | 2246 | CARLYLE | MT |
| — | 406-589 | 0–9 XXXall 10 · 4 holders which blocks → | T-MOBILE USA, INC. | 6529 | BOZEMAN | MT |
| — | 406-590 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT | 6564 | GREATFALLS | MT |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/28/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.