NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 661-617

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 661-617 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
LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 5
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 3
U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 1
TELEPORT COMMUNICATIONS AMERICA, LLC - 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
2008-06-09 661-617-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 BKFD SOUTH CA
— 661-617-1XXX 1000–1999Reserved LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 BKFD SOUTH CA
2009-07-31 661-617-2XXX 2000–2999Assigned LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 BKFD SOUTH CA
— 661-617-3XXX 3000–3999Reserved LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 BKFD SOUTH CA
— 661-617-4XXX 4000–4999Reserved LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 BKFD SOUTH CA
2009-06-11 661-617-5XXX 5000–5999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7139 BKFD SOUTH CA
2004-05-11 661-617-6XXX 6000–6999Assigned U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J BKFD SOUTH CA
2011-05-09 661-617-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 BKFD SOUTH CA
2008-06-02 661-617-8XXX 8000–8999Assigned LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 BKFD SOUTH CA
2009-09-23 661-617-9XXX 9000–9999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 BKFD SOUTH 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.