NumberResearchThousands-blocks in 551-221
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
The ten 1,000-number thousand-blocks inside prefix 551-221 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 551 blocks
Most active assignees, all time — NPA 551
New assignments by month
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| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 551-221-0XXX | 0000–0999 | Reserved | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| — | 551-221-1XXX | 1000–1999 | Reserved | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| — | 551-221-2XXX | 2000–2999 | Reserved | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| 2008-01-04 | 551-221-3XXX | 3000–3999 | Assigned | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| 2005-05-13 | 551-221-4XXX | 4000–4999 | Assigned | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| 2006-12-27 | 551-221-5XXX | 5000–5999 | Assigned | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| — | 551-221-6XXX | 6000–6999 | Reserved | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| 2007-07-18 | 551-221-7XXX | 7000–7999 | Assigned | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
| 2020-04-29 | 551-221-8XXX | 8000–8999 | Assigned | IP HORIZON LLC | 515J | BAYONNE | NJ |
| — | 551-221-9XXX | 9000–9999 | Reserved | OMNIPOINT COMMUNICATIONS, INC. - NJ | 6623 | BAYONNE | NJ |
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.