NumberResearch Membership · Data 09/19/2026

Thousands-blocks in 203-604

This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/19/2026

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

The ten 1,000-number thousand-blocks inside prefix 203-604 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 203 blocks

Most active assignees, all time — NPA 203
LEVEL 3 COMMUNICATIONS, LLC - CT 5
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 3
PAETEC ITEL, LLC 1
NEW CINGULAR WIRELESS PCS, LLC - DC 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
Clear Download CSV ↓
Recent thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
2005-02-14 203-604-0XXX 0000–0999Assigned LEVEL 3 COMMUNICATIONS, LLC - CT 4800 NORWALK CT
2003-11-12 203-604-1XXX 1000–1999Assigned PAETEC ITEL, LLC 829J NORWALK CT
2004-08-16 203-604-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - CT 4800 NORWALK CT
2014-04-17 203-604-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 NORWALK CT
2010-06-04 203-604-4XXX 4000–4999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 NORWALK CT
2011-01-05 203-604-5XXX 5000–5999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 NORWALK CT
2005-10-05 203-604-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - CT 4800 NORWALK CT
2011-08-08 203-604-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 NORWALK CT
2002-06-14 203-604-8XXX 8000–8999Assigned LEVEL 3 COMMUNICATIONS, LLC - CT 4800 NORWALK CT
2005-05-10 203-604-9XXX 9000–9999Assigned LEVEL 3 COMMUNICATIONS, LLC - CT 4800 NORWALK CT

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.