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 307
UNION TELEPHONE COMPANY 65
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
2007-11-06 307-798 not yet reported which blocks → UNION TELEPHONE COMPANY 013B ROCK RIVER WY
2003-12-18 307-790 not yet reported which blocks → UNION TELEPHONE COMPANY 013B SUNDANCE WY
2003-10-20 307-749 not yet reported which blocks → UNION TELEPHONE COMPANY 013B PINEDALE WY
2003-10-20 307-759 not yet reported which blocks → UNION TELEPHONE COMPANY 013B LUSK WY
2003-10-20 307-779 not yet reported which blocks → UNION TELEPHONE COMPANY 013B WHEATLAND WY
2003-06-26 307-707 not yet reported which blocks → UNION TELEPHONE COMPANY 013B GREENRIVER WY
2003-06-16 307-705 not yet reported which blocks → UNION TELEPHONE COMPANY 013B ROCK SPG WY
2003-06-16 307-708 not yet reported which blocks → UNION TELEPHONE COMPANY 013B EVANSTON WY
2003-06-16 307-709 not yet reported which blocks → UNION TELEPHONE COMPANY 013B RIVERTON WY
2003-06-16 307-710 not yet reported which blocks → UNION TELEPHONE COMPANY 013B RAWLINS WY
2003-06-16 307-713 not yet reported which blocks → UNION TELEPHONE COMPANY 013B JACKSON WY
2003-06-16 307-714 not yet reported which blocks → UNION TELEPHONE COMPANY 013B LANDER WY
2003-06-16 307-723 not yet reported which blocks → UNION TELEPHONE COMPANY 013B KEMMERER WY
2003-06-16 307-724 not yet reported which blocks → UNION TELEPHONE COMPANY 013B CASPER WY
2003-06-16 307-747 not yet reported which blocks → UNION TELEPHONE COMPANY 013B MT VIEW WY
2002-12-27 307-701 not yet reported which blocks → UNION TELEPHONE COMPANY 013B CHEYENNE WY
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
2001-03-27 307-354 not yet reported which blocks → UNION TELEPHONE COMPANY 013B ROCK SPG WY
— 307-260 not yet reported which blocks → UNION TELEPHONE COMPANY 013B BIG PINEY WY
— 307-270 not yet reported which blocks → UNION TELEPHONE COMPANY 013B COKEVILLE WY
— 307-280 not yet reported which blocks → UNION TELEPHONE COMPANY 013B FARSON WY
— 307-320 not yet reported which blocks → UNION TELEPHONE COMPANY 013B RAWLINS WY
— 307-329 not yet reported which blocks → UNION TELEPHONE COMPANY 013B SARATOGA WY
— 307-330 not yet reported which blocks → UNION TELEPHONE COMPANY 013B LANDER WY
— 307-339 not yet reported which blocks → UNION TELEPHONE COMPANY 013B HANNA WY
— 307-345 not yet reported which blocks → UNION TELEPHONE COMPANY 013B LANDER WY
— 307-350 not yet reported which blocks → UNION TELEPHONE COMPANY 013B ROCK SPG WY
— 307-360 not yet reported which blocks → UNION TELEPHONE COMPANY 013B PINEDALE WY
— 307-377 not yet reported which blocks → UNION TELEPHONE COMPANY 013B CASPER WY
— 307-380 not yet reported which blocks → UNION TELEPHONE COMPANY 013B BAGGS WY
— 307-390 not yet reported which blocks → UNION TELEPHONE COMPANY 013B LABARGE WY
— 307-450 not yet reported which blocks → UNION TELEPHONE COMPANY 013B DUBOIS WY
— 307-477 not yet reported which blocks → UNION TELEPHONE COMPANY 013B CHEYENNE WY
— 307-520 not yet reported which blocks → UNION TELEPHONE COMPANY 013B MEDICINBOW 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

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.