NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

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
QWEST CORPORATION 132
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 119
NEW CINGULAR WIRELESS PCS, LLC 74
ONVOY, LLC - MT 43
TRIANGLE TEL. COOP. ASSN., INC. 39
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
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2017-04-27 406-400 0–9 XXXall 10 · 2 holders which blocks → TRIANGLE COMMUNICATION SYSTEM, INC. - MT- 958H HAVRE MT
2017-03-24 406-916 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 HELENA MT
2017-03-22 406-510 0–9 XXXwhole prefix which blocks → ONVOY, LLC - MT 453F MISSOULA MT
2016-12-21 406-831 0–9 XXXall 10 · 6 holders which blocks → TELNYX LLC 073H BILLINGS MT
2016-09-08 406-729 0–9 XXXall 10 · 4 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J WILSALL MT
2016-06-03 406-970 0–9 XXXall 10 · 5 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J BILLINGS MT
2016-03-25 406-304 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 MISSOULA MT
2015-08-26 406-998 0–9 XXXall 10 · 4 holders which blocks → AIRUS, INC. - MT 588H BILLINGS MT
2015-07-15 406-936 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MT 994E CLYDE PARK MT
2015-05-12 406-413 0–9 XXXall 10 · 6 holders which blocks → QWEST CORPORATION 9636 BILLINGS MT
2014-04-28 406-615 2XXX which blocks → WESTERN MONTANA COMMUNITYTEL INC. - MT 986F THOMPSNFLS MT
2014-02-10 406-688 6XXX8XXX9XXX · 2 holders which blocks → SAGEBRUSH CELLULAR, INC. 443B SCOBEY MT
2014-02-06 406-438 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 6564 HELENA MT
2013-12-11 406-800 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - MT 453F BRIDGER MT
2013-11-08 406-601 0–9 XXXall 10 · 7 holders which blocks → BLACKFOOT COMMUNICATIONS, INC. - MT 7870 BILLINGS MT
2013-11-08 406-602 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 6 holders which blocks → BLACKFOOT COMMUNICATIONS, INC. - MT 7870 BOZEMAN MT
2013-11-08 406-603 0XXX4XXX · 2 holders which blocks → BLACKFOOT COMMUNICATIONS, INC. - MT 7870 HELENA MT
2013-11-08 406-607 0–9 XXXall 10 · 4 holders which blocks → BLACKFOOT COMMUNICATIONS, INC. - MT 7870 KALISPELL MT
2013-10-03 406-479 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 6564 BUTTE MT
2013-09-18 406-389 0–9 XXXall 10 · 3 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J HELENA MT
2013-07-17 406-300 0–9 XXXall 10 · 6 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K KALISPELL MT
2013-03-01 406-878 2XXX8XXX · 2 holders which blocks → NUSO, LLC 732J GREATFALLS MT
2012-12-07 406-606 0–9 XXXall 10 · 4 holders which blocks → TRI TEL, INC. - MT 935G BILLINGS MT
2012-11-16 406-313 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - MT 453F BOULDER MT
2012-11-16 406-744 2XXX4XXX · 2 holders which blocks → WESTERN MONTANA COMMUNITYTEL INC. - MT 986F STIGNATIUS MT
2012-04-17 406-200 0–9 XXXall 10 · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA MT - LLC 771G BILLINGS MT
2012-04-17 406-303 0–9 XXXall 10 · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA MT - LLC 771G MISSOULA MT
2012-04-03 406-404 0–9 XXXall 10 · 4 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K BOZEMAN MT
2012-04-03 406-502 1XXX2XXX8XXX · 2 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K HELENA MT
2012-03-07 406-702 0–9 XXXall 10 · 3 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K BILLINGS MT
2012-02-03 406-508 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MT 9415 FRENCHTOWN MT
2011-12-07 406-414 0–9 XXXall 10 · 3 holders which blocks → QWEST CORPORATION 9636 BOZEMAN MT
2011-10-03 406-302 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - MT 453F WOLF CREEK MT
2011-10-03 406-812 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - MT 453F LAUREL MT
2011-10-03 406-905 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - MT 453F JOLIET MT
2011-09-27 406-518 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - MT 453F GALATNGTWY MT
2011-09-14 406-813 0–9 XXXall 10 · 6 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BELGRADE MT
2011-07-15 406-604 0–9 XXXall 10 · 5 holders which blocks → BLACKFOOT COMMUNICATIONS, INC. - MT 7870 GREATFALLS MT
2011-07-01 406-309 0–9 XXXall 10 · 6 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K KALISPELL MT
2011-07-01 406-616 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - MT 453F THREEFORKS MT
2011-06-09 406-361 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 6564 HAMILTON MT
2011-02-17 406-318 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - MT 453F BILLINGS MT
2011-01-10 406-996 1XXX which blocks → CHARTER IP ENABLED SERVICES, LLC 792K HELENA MT
2011-01-07 406-926 0–9 XXXall 10 · 3 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K MISSOULA MT
2010-10-20 406-305 0XXX1XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 WHSLPHRSPG MT
2010-10-20 406-514 0XXX1XXX2XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 CULBERTSON MT
2010-10-20 406-956 0XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 BAKER MT
2010-10-14 406-505 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 CONRAD MT
2010-10-12 406-269 none assigned yet which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 ST REGIS MT
2010-10-12 406-515 5XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 SUPERIOR 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.