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 571
LEVEL 3 COMMUNICATIONS, LLC - VA 20
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
2026-05-07 571-763 0–9 XXXwhole prefix which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN17 VA
2019-12-20 571-496 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 LORTONMTRO VA
2019-08-13 571-695 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN17 VA
2019-08-01 571-415 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 HAYMARKET VA
2019-03-28 571-833 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 MANASSAS VA
2018-05-30 571-347 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN08 VA
2017-09-29 571-495 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN19 VA
2016-06-09 571-260 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 DALE CITY VA
2014-08-08 571-446 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 HERNDON VA
2013-12-13 571-343 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 OCCOQUAN VA
2011-12-05 571-254 0–9 XXXwhole prefix which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 TRIANGLE VA
2011-05-10 571-388 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN08 VA
2010-12-21 571-421 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN17 VA
2007-08-09 571-297 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN17 VA
2005-05-24 571-291 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 LEESBURG VA
2001-05-23 571-222 0XXX2XXX3XXX4XXX5XXX6XXX7XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 HAYMARKET VA
— 571-281 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 BRADDOCK VA
— 571-341 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN17 VA
— 571-723 0–9 XXXall 10 · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 WSNGTNZN19 VA
— 571-831 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - VA 8825 LEESBURG VA

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.