NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

2 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, last 30 days — NPA 307
UINTAH BASIN ELECTRONIC TELECOMMUNICATIONS 2
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
2002-12-27 307-702 not yet reported which blocks → UNION TELEPHONE COMPANY 013B CASPER WY
2002-12-27 307-703 not yet reported which blocks → UNION TELEPHONE COMPANY 013B LARAMIE WY
2002-12-27 307-704 not yet reported which blocks → UNION TELEPHONE COMPANY 013B GILLETTE WY
2002-12-27 307-706 not yet reported which blocks → UNION TELEPHONE COMPANY 013B SHERIDAN WY
2002-12-27 307-712 not yet reported which blocks → UNION TELEPHONE COMPANY 013B CODY WY
2002-12-27 307-715 not yet reported which blocks → UNION TELEPHONE COMPANY 013B TORRINGTON WY
2002-12-27 307-716 not yet reported which blocks → UNION TELEPHONE COMPANY 013B POWELL WY
2002-12-27 307-717 not yet reported which blocks → UNION TELEPHONE COMPANY 013B DOUGLAS WY
2002-12-27 307-718 not yet reported which blocks → UNION TELEPHONE COMPANY 013B WORLAND WY
2002-12-27 307-719 not yet reported which blocks → UNION TELEPHONE COMPANY 013B BUFFALO WY
2002-12-27 307-720 not yet reported which blocks → UNION TELEPHONE COMPANY 013B WHEATLAND WY
2002-12-27 307-722 not yet reported which blocks → UNION TELEPHONE COMPANY 013B THERMOPOLS WY
2002-12-27 307-731 not yet reported which blocks → UNION TELEPHONE COMPANY 013B LOVELL WY
2002-12-27 307-741 not yet reported which blocks → UNION TELEPHONE COMPANY 013B GLENROCK WY
2002-12-27 307-744 not yet reported which blocks → UNION TELEPHONE COMPANY 013B NEWCASTLE WY
2002-10-09 307-216 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 LUSK WY
2002-10-09 307-217 4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 BUFFALO WY
2002-08-16 307-200 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 JACKSON WY
2002-07-16 307-212 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 ROCK SPG WY
2002-07-16 307-213 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 CODY WY
2002-07-15 307-255 not yet reported which blocks → UINTAH BASIN ELECTRONIC TELECOMMUNICATIONS 1772 EVANSTON WY
2002-06-28 307-575 7XXX8XXX · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 TORRINGTON WY
2002-06-11 307-459 0XXX1XXX2XXX3XXX5XXX6XXX8XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 CHEYENNE WY
2002-06-11 307-460 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 LARAMIE WY
2002-06-11 307-461 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 SHERIDAN WY
2002-06-11 307-462 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 CASPER WY
2002-06-11 307-463 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 RIVERTON WY
2002-05-16 307-399 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 LARAMIE WY
2001-10-03 307-624 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 8 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 DOUGLAS WY
2001-10-03 307-797 7XXX8XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 CASPER WY
2001-07-26 307-215 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - WY 081F CASPER WY
2001-03-27 307-354 not yet reported which blocks → UNION TELEPHONE COMPANY 013B ROCK SPG WY
2001-03-14 307-203 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 JACKSON WY
2001-01-29 307-413 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 JACKSON WY
— 307-208 not yet reported which blocks → WY
— 307-211 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX WY
— 307-220 4XXX5XXX6XXX9XXX which blocks → T-MOBILE USA, INC. 6529 CHEYENNE WY
— 307-221 8XXX which blocks → T-MOBILE USA, INC. 6529 CHEYENNE WY
— 307-222 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 CHEYENNE WY
— 307-223 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 LARAMIE WY
— 307-224 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - WY 9416 CASPER WY
— 307-227 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - WY 450F MAMMOTH WY
— 307-231 7XXX which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 PINEDALE WY
— 307-232 not yet reported which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-233 not yet reported which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-234 not yet reported which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-235 not yet reported which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-237 not yet reported which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-240 2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 RIVERTON WY
— 307-241 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 WHEATLAND WY

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.