NumberResearchThousands-blocks in 231-539
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 231-539 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 231 blocks
Most active assignees, all time — NPA 231
New assignments by month
Sep 2026
Aug 2026
Jul 2026
Jun 2026
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Dec 2025
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2013-02-20 | 231-539-0XXX | 0000–0999 | Assigned | ONVOY, LLCV - MI | 543C | PELLSTON | MI |
| 2004-10-14 | 231-539-1XXX | 1000–1999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MI | 6120 | PELLSTON | MI |
| 2005-01-18 | 231-539-2XXX | 2000–2999 | Assigned | ACD TELECOM, INC. - MI | 3535 | PELLSTON | MI |
| 2008-08-15 | 231-539-3XXX | 3000–3999 | Assigned | CHARTER IP ENABLED SERVICES, LLC | 792K | PELLSTON | MI |
| 2004-01-12 | 231-539-4XXX | 4000–4999 | Assigned | PAETEC ITEL, LLC | 829J | PELLSTON | MI |
| 2005-08-03 | 231-539-5XXX | 5000–5999 | Assigned | TELNET WORLDWIDE, INC. | 817J | PELLSTON | MI |
| 2023-07-07 | 231-539-6XXX | 6000–6999 | Assigned | ONVOY, LLCV - MI | 543C | PELLSTON | MI |
| — | 231-539-7XXX | 7000–7999 | Reserved | MICHIGAN BELL TEL CO | 9323 | PELLSTON | MI |
| — | 231-539-8XXX | 8000–8999 | Reserved | MICHIGAN BELL TEL CO | 9323 | PELLSTON | MI |
| 2011-08-11 | 231-539-9XXX | 9000–9999 | Assigned | AT&T ENTERPRISES, LLC | 516C | PELLSTON | 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.