NumberResearchThousands-blocks in 251-357
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 251-357 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 251 blocks
Most active assignees, all time — NPA 251
New assignments by month
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2010-05-25 | 251-357-0XXX | 0000–0999 | Assigned | MCC TELEPHONY OF THE SOUTH, LLC - AL | 773F | HUXFORD | AL |
| 2019-03-14 | 251-357-1XXX | 1000–1999 | Assigned | ONVOY, LLC - AL | 604E | HUXFORD | AL |
| 2020-04-08 | 251-357-2XXX | 2000–2999 | Assigned | TELNYX LLC | 073H | HUXFORD | AL |
| 2020-08-05 | 251-357-3XXX | 3000–3999 | Assigned | ONVOY SPECTRUM, LLC | 624H | HUXFORD | AL |
| 2021-02-01 | 251-357-4XXX | 4000–4999 | Assigned | ONVOY SPECTRUM, LLC | 624H | HUXFORD | AL |
| — | 251-357-5XXX | 5000–5999 | Available | HUXFORD | AL | ||
| 2021-01-19 | 251-357-6XXX | 6000–6999 | Assigned | ONVOY, LLC - AL | 604E | HUXFORD | AL |
| — | 251-357-7XXX | 7000–7999 | Available | HUXFORD | AL | ||
| 2018-12-04 | 251-357-8XXX | 8000–8999 | Assigned | ONVOY, LLC - AL | 604E | HUXFORD | AL |
| 2018-12-04 | 251-357-9XXX | 9000–9999 | Assigned | ONVOY, LLC - AL | 604E | HUXFORD | AL |
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.