NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 661-800

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 661-800 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 661 blocks

Most active assignees, all time — NPA 661
T-MOBILE USA, INC. 3
METROPCS, INC. 3
ONVOY, LLC - CA 1
LEVEL 3 COMMUNICATIONS, LLC - CA 1
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 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
2010-11-03 661-800-0XXX 0000–0999Assigned ONVOY, LLC - CA 649C BKFD MAIN CA
2011-12-16 661-800-1XXX 1000–1999Assigned METROPCS, INC. 5562 BKFD MAIN CA
2011-12-16 661-800-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 BKFD MAIN CA
2012-02-17 661-800-3XXX 3000–3999Assigned METROPCS, INC. 5562 BKFD MAIN CA
2011-06-16 661-800-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - CA 8826 BKFD MAIN CA
2012-01-26 661-800-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C BKFD MAIN CA
2011-02-23 661-800-6XXX 6000–6999Assigned METROPCS, INC. 5562 BKFD MAIN CA
2012-02-17 661-800-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 BKFD MAIN CA
2011-03-08 661-800-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 BKFD MAIN CA
2021-10-28 661-800-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 BKFD MAIN CA

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.