NumberResearchThousands-blocks in 515-581
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 515-581 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
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2021-12-08 | 515-581-0XXX | 0000–0999 | Assigned | UNITED STATES CELLULAR - IA | 6266 | ADEL | IA |
| 2022-05-31 | 515-581-1XXX | 1000–1999 | Assigned | T-MOBILE USA, INC. | 6529 | ADEL | IA |
| 2022-05-31 | 515-581-2XXX | 2000–2999 | Assigned | METROPCS, INC. | 5562 | ADEL | IA |
| — | 515-581-3XXX | 3000–3999 | Available | ADEL | IA | ||
| 2023-06-27 | 515-581-4XXX | 4000–4999 | Assigned | ONVOY, LLC - IA | 221F | ADEL | IA |
| 2023-09-18 | 515-581-5XXX | 5000–5999 | Assigned | ONVOY, LLC - IA | 221F | ADEL | IA |
| 2022-03-12 | 515-581-6XXX | 6000–6999 | Assigned | MINBURN TELEPHONE COMPANY - IA | 143H | ADEL | IA |
| 2022-12-06 | 515-581-7XXX | 7000–7999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - IA | 9877 | ADEL | IA |
| 2023-09-18 | 515-581-8XXX | 8000–8999 | Assigned | ONVOY, LLC - IA | 221F | ADEL | IA |
| 2022-05-18 | 515-581-9XXX | 9000–9999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC - IL | 6534 | ADEL | IA |
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.