NumberResearchThousands-blocks in 517-878
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 517-878 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 517 blocks
Most active assignees, all time — NPA 517
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2021-06-11 | 517-878-0XXX | 0000–0999 | Assigned | ONVOY, LLCV - MI | 543C | LESLIE | MI |
| 2012-12-03 | 517-878-1XXX | 1000–1999 | Assigned | ONVOY, LLCV - MI | 543C | LESLIE | MI |
| 2012-05-01 | 517-878-2XXX | 2000–2999 | Assigned | ONVOY, LLCV - MI | 543C | LESLIE | MI |
| 2013-10-10 | 517-878-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | LESLIE | MI |
| 2005-12-01 | 517-878-4XXX | 4000–4999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MI | 6120 | LESLIE | MI |
| 2008-05-07 | 517-878-5XXX | 5000–5999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MI | 6120 | LESLIE | MI |
| 2012-05-02 | 517-878-6XXX | 6000–6999 | Assigned | WOW! INTERNET, CABLE AND PHONE | 961J | LESLIE | MI |
| 2007-02-06 | 517-878-7XXX | 7000–7999 | Assigned | ONVOY, LLCV - MI | 543C | LESLIE | MI |
| — | 517-878-8XXX | 8000–8999 | Available | LESLIE | MI | ||
| 2013-01-03 | 517-878-9XXX | 9000–9999 | Assigned | ONVOY, LLCV - MI | 543C | LESLIE | MI |
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.