NumberResearchThousands-blocks in 517-858
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 517-858 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
Aug 2026
Jul 2026
Jun 2026
May 2026
Apr 2026
Mar 2026
Feb 2026
Jan 2026
Dec 2025
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2006-04-12 | 517-858-0XXX | 0000–0999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MI | 6120 | BRONSON | MI |
| 2007-01-24 | 517-858-1XXX | 1000–1999 | Assigned | CHARTER IP ENABLED SERVICES, LLC | 792K | BRONSON | MI |
| 2020-04-02 | 517-858-2XXX | 2000–2999 | Assigned | BANDWIDTH.COM CLEC, LLC - MI | 991E | BRONSON | MI |
| — | 517-858-3XXX | 3000–3999 | Available | BRONSON | MI | ||
| — | 517-858-4XXX | 4000–4999 | Reserved | LEVEL 3 COMMUNICATIONS, LLC - MI | 6120 | BRONSON | MI |
| 2016-11-09 | 517-858-5XXX | 5000–5999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - MI | 770E | BRONSON | MI |
| 2024-05-07 | 517-858-6XXX | 6000–6999 | Assigned | ONVOY SPECTRUM, LLC | 624H | BRONSON | MI |
| 2015-08-12 | 517-858-7XXX | 7000–7999 | Assigned | CENTURYLINK COMMUNICATIONS, LLC | 508J | BRONSON | MI |
| 2021-06-15 | 517-858-8XXX | 8000–8999 | Assigned | ONVOY, LLCV - MI | 543C | BRONSON | MI |
| 2020-11-04 | 517-858-9XXX | 9000–9999 | Assigned | BANDWIDTH.COM CLEC, LLC - MI | 991E | BRONSON | MI |
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.