NumberResearchThousands-blocks in 603-509
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
The ten 1,000-number thousand-blocks inside prefix 603-509 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 603 blocks
Most active assignees, all time — NPA 603
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2006-02-16 | 603-509-0XXX | 0000–0999 | Assigned | METROPCS, INC. | 5562 | ROCHESTER | NH |
| 2001-09-25 | 603-509-1XXX | 1000–1999 | Assigned | PAETEC ITEL, LLC | 829J | ROCHESTER | NH |
| 2005-04-07 | 603-509-2XXX | 2000–2999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - NH | 4017 | ROCHESTER | NH |
| 2005-04-07 | 603-509-3XXX | 3000–3999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - NH | 4017 | ROCHESTER | NH |
| 2002-09-07 | 603-509-4XXX | 4000–4999 | Assigned | OTEL TELEKOM, INC. - NH | 9827 | ROCHESTER | NH |
| — | 603-509-5XXX | 5000–5999 | Available | ROCHESTER | NH | ||
| 2014-11-21 | 603-509-6XXX | 6000–6999 | Assigned | METROPCS, INC. | 5562 | ROCHESTER | NH |
| 2023-10-13 | 603-509-7XXX | 7000–7999 | Assigned | TERRA NOVA TELECOM INC. | 145J | ROCHESTER | NH |
| 2015-06-23 | 603-509-8XXX | 8000–8999 | Assigned | BELL ATLANTIC MOBILE, INC | 6386 | ROCHESTER | NH |
| 2010-09-14 | 603-509-9XXX | 9000–9999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - NH | 4017 | ROCHESTER | NH |
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.