NumberResearchThousands-blocks in 515-257
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 515-257 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 515 blocks
Most active assignees, all time — NPA 515
New assignments by month
Sep 2026
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Dec 2025
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2008-08-04 | 515-257-0XXX | 0000–0999 | Assigned | T-MOBILE USA, INC. | 6529 | DES MOINES | IA |
| 2008-05-05 | 515-257-1XXX | 1000–1999 | Assigned | ONVOY, LLC - IA | 221F | DES MOINES | IA |
| 2025-03-21 | 515-257-2XXX | 2000–2999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC - IL | 6534 | DES MOINES | IA |
| 2009-02-13 | 515-257-3XXX | 3000–3999 | Assigned | T-MOBILE USA, INC. | 6529 | DES MOINES | IA |
| 2005-03-02 | 515-257-4XXX | 4000–4999 | Assigned | MCC TELEPHONY OF IOWA, LLC - IA | 751F | DES MOINES | IA |
| 2008-08-14 | 515-257-5XXX | 5000–5999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - IA | 8344 | DES MOINES | IA |
| 2008-10-30 | 515-257-6XXX | 6000–6999 | Assigned | BANDWIDTH.COM CLEC, LLC - IA | 985E | DES MOINES | IA |
| 2008-01-28 | 515-257-7XXX | 7000–7999 | Assigned | ONVOY, LLC - IA | 221F | DES MOINES | IA |
| 2007-01-25 | 515-257-8XXX | 8000–8999 | Assigned | MCC TELEPHONY OF IOWA, LLC - IA | 751F | DES MOINES | IA |
| — | 515-257-9XXX | 9000–9999 | Reserved | TELEPORT COMMUNICATIONS AMERICA, LLC - IA | 8344 | DES MOINES | IA |
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.