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 443
LEVEL 3 COMMUNICATIONS, LLC - MD 69
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
2014-06-13 443-809 0–9 XXXwhole prefix which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 TOWSON MD
2012-05-23 443-666 0–9 XXXall 10 · 9 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 CHESTERTN MD
2006-06-08 443-988 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 CENTREVL MD
2006-05-12 443-964 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 NORTHBEACH MD
2005-12-30 443-818 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ARGRGBSNIS MD
2005-12-08 443-898 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 PIKESVILLE MD
2005-02-03 443-740 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BALTIMORE MD
2002-02-22 443-746 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 EASTON MD
2001-06-20 443-403 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ABERDEEN MD
2001-05-18 443-545 0XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 COLUMBIA MD
2001-05-18 443-641 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 PIKESVILLE MD
2001-02-21 443-625 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 FORK MD
— 443-218 0XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WORTHINGTN MD
— 443-219 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 PARKVILLE MD
— 443-221 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ANNAPOLIS MD
— 443-244 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WESTMINSTR MD
— 443-291 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 HAMPSTEAD MD
— 443-292 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 CROFTON MD
— 443-295 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 PRINCEFRCK MD
— 443-296 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WATERLO238 MD
— 443-300 0XXX1XXX3XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 SYKESVILLE MD
— 443-302 0XXX1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 CROFTON MD
— 443-303 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ABERDEEN MD
— 443-305 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ARGRGBSNIS MD
— 443-307 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BEL AIR MD
— 443-312 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BRYNPKLNCM MD
— 443-313 0XXX1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 FORK MD
— 443-316 0XXX1XXX2XXX3XXX4XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WOODLAWN MD
— 443-320 0XXX3XXX6XXX7XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BALTIMORE MD
— 443-329 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WATERLO236 MD
— 443-341 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 CATONSVL MD
— 443-345 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ABERDEEN MD
— 443-352 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 PIKESVILLE MD
— 443-354 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 GLENBURNIE MD
— 443-355 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ELLICOTTCY MD
— 443-356 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BEL AIR MD
— 443-371 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BEL AIR MD
— 443-380 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WOODLAWN MD
— 443-391 2XXX3XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 COCKEYSVL MD
— 443-393 0XXX1XXX2XXX3XXX6XXX7XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 COLUMBIA MD
— 443-396 0XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ODENTON MD
— 443-423 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BALTIMORE MD
— 443-450 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 PIKESVILLE MD
— 443-472 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 COLUMBIA MD
— 443-483 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 CARDIFF MD
— 443-484 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 EDGEWOOD MD
— 443-485 0–9 XXXall 10 · 8 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ELKTON MD
— 443-486 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 PRINCEFRCK MD
— 443-487 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WESTMINSTR MD
— 443-492 2XXX3XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ELKRIDGE MD

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.