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
— 307-450 not yet reported which blocks → UNION TELEPHONE COMPANY 013B DUBOIS WY
— 307-455 not yet reported which blocks → DUBOIS TEL. EXCH., INC. 2291 DUBOIS WY
— 307-457 not yet reported which blocks → RT COMMUNICATIONS 3410 GAS HILLS WY
— 307-464 3XXX7XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 WRIGHT WY
— 307-465 not yet reported which blocks → RT COMMUNICATIONS 3410 NEWCASTLE WY
— 307-466 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 GREENRIVER WY
— 307-467 not yet reported which blocks → RT COMMUNICATIONS 3410 HULETT WY
— 307-468 not yet reported which blocks → RT COMMUNICATIONS 3410 UPTON WY
— 307-469 not yet reported which blocks → TRI-COUNTY TEL. ASSN., INC. 2296 HYATTVILLE WY
— 307-470 not yet reported which blocks → WY
— 307-472 not yet reported which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-473 0XXX which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-477 not yet reported which blocks → UNION TELEPHONE COMPANY 013B CHEYENNE WY
— 307-486 not yet reported which blocks → DUBOIS TEL. EXCH., INC. 2291 CROWHEART WY
— 307-497 not yet reported which blocks → ALL WEST COMMUNICATIONS - WY 2290 EVANSTON WY
— 307-511 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX WY
— 307-514 0XXX1XXX2XXX3XXX4XXX5XXX6XXX9XXX which blocks → CHARTER IP ENABLED SERVICES, LLC 792K CHEYENNE WY
— 307-520 not yet reported which blocks → UNION TELEPHONE COMPANY 013B MEDICINBOW WY
— 307-527 0XXX which blocks → QWEST CORPORATION 9636 CODY WY
— 307-532 not yet reported which blocks → UNITED TEL CO WEST - WY DBA CENTURYLINK WEST - WY 4531 TORRINGTON WY
— 307-534 none assigned yet which blocks → UNITED TEL CO WEST - WY DBA CENTURYLINK WEST - WY 4531 TORRINGTON WY
— 307-536 not yet reported which blocks → WY
— 307-537 not yet reported which blocks → CENTURYTEL OF WYOMING, INC. DBA CENTURYLINK 2299 PINEDALE WY
— 307-540 not yet reported which blocks → UNION TELEPHONE COMPANY 013B JEFFREY CY WY
— 307-541 not yet reported which blocks → UNION TELEPHONE COMPANY 013B MORAN WY
— 307-543 1XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → QWEST CORPORATION 9636 MORAN WY
— 307-544 not yet reported which blocks → RT COMMUNICATIONS 3410 JEFFREY CY WY
— 307-545 0XXX1XXX3XXX5XXX6XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9636 OLDFATHFUL WY
— 307-547 not yet reported which blocks → RT COMMUNICATIONS 3410 BURNS WY
— 307-548 not yet reported which blocks → TRI-COUNTY TEL. ASSN., INC. 2296 LOVELL WY
— 307-549 not yet reported which blocks → UNION TELEPHONE COMPANY 013B OLDFATHFUL WY
— 307-554 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - WY 450F GLENROCK WY
— 307-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST WY
— 307-558 not yet reported which blocks → WY
— 307-559 not yet reported which blocks → WY
— 307-567 not yet reported which blocks → UNION TELEPHONE COMPANY 013B GILLETTE WY
— 307-568 not yet reported which blocks → TRI-COUNTY TEL. ASSN., INC. 2296 BASIN WY
— 307-576 not yet reported which blocks → COLUMBINE TELCO DBA SILVER STAR COMMUNICATIONS 2214 LEIGHCNYON WY
— 307-577 not yet reported which blocks → QWEST CORPORATION 9636 CASPER WY
— 307-578 6XXX7XXX8XXX9XXX · 3 holders which blocks → QWEST CORPORATION 9636 CODY WY
— 307-587 not yet reported which blocks → QWEST CORPORATION 9636 CODY WY
— 307-600 not yet reported which blocks → UNION TELEPHONE COMPANY 013B COKEVILLE WY
— 307-605 not yet reported which blocks → WY
— 307-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX WY
— 307-620 3XXX4XXX6XXX7XXX8XXX · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 BUFFALO WY
— 307-621 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 BUFFALO WY
— 307-630 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 CHEYENNE WY
— 307-631 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 6566 CHEYENNE WY
— 307-632 not yet reported which blocks → QWEST CORPORATION 9636 CHEYENNE WY
— 307-633 1XXX which blocks → QWEST CORPORATION 9636 CHEYENNE 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.