NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 610-257

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 610-257 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 610 blocks

Most active assignees, all time — NPA 610
CORE COMMUNICATIONS, INC. - PA 5
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - PA 3
NEW CINGULAR WIRELESS PCS, LLC - DC 1
BANDWIDTH.COM CLEC, LLC - PA 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
2019-04-04 610-257-0XXX 0000–0999Assigned CORE COMMUNICATIONS, INC. - PA 3806 PHPHSBZN23 PA
2019-04-04 610-257-1XXX 1000–1999Assigned CORE COMMUNICATIONS, INC. - PA 3806 PHPHSBZN23 PA
2024-09-10 610-257-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 PHPHSBZN23 PA
— 610-257-3XXX 3000–3999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC - PA 7434 PHPHSBZN23 PA
2019-03-12 610-257-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC. - PA 3806 PHPHSBZN23 PA
— 610-257-5XXX 5000–5999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC - PA 7434 PHPHSBZN23 PA
2019-04-04 610-257-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC. - PA 3806 PHPHSBZN23 PA
2013-02-04 610-257-7XXX 7000–7999Assigned BANDWIDTH.COM CLEC, LLC - PA 002F PHPHSBZN23 PA
2019-04-04 610-257-8XXX 8000–8999Assigned CORE COMMUNICATIONS, INC. - PA 3806 PHPHSBZN23 PA
— 610-257-9XXX 9000–9999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC - PA 7434 PHPHSBZN23 PA

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.