NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 517-781

This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/20/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The ten 1,000-number thousand-blocks inside prefix 517-781 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 517 blocks

Most active assignees, all time — NPA 517
LEVEL 3 COMMUNICATIONS, LLC - MI 3
ONVOY, LLCV - MI 2
ONVOY SPECTRUM, LLC 2
OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI 1
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 thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
2005-06-07 517-781-0XXX 0000–0999Assigned OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 COLDWATER MI
2021-02-25 517-781-1XXX 1000–1999Assigned OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 COLDWATER MI
2021-12-17 517-781-2XXX 2000–2999Assigned ONVOY SPECTRUM, LLC 624H COLDWATER MI
2020-06-29 517-781-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI 7157 COLDWATER MI
— 517-781-4XXX 4000–4999Reserved LEVEL 3 COMMUNICATIONS, LLC - MI 6120 COLDWATER MI
2005-06-08 517-781-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - MI 6120 COLDWATER MI
2005-06-08 517-781-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - MI 6120 COLDWATER MI
2019-04-05 517-781-7XXX 7000–7999Assigned ONVOY, LLCV - MI 543C COLDWATER MI
2019-04-05 517-781-8XXX 8000–8999Assigned ONVOY, LLCV - MI 543C COLDWATER MI
2021-12-17 517-781-9XXX 9000–9999Assigned ONVOY SPECTRUM, LLC 624H COLDWATER MI

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.