NumberResearchThousands-blocks in 313-756
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 313-756 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 313 blocks
Most active assignees, all time — NPA 313
New assignments by month
Sep 2026
Aug 2026
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Dec 2025
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2021-01-25 | 313-756-0XXX | 0000–0999 | Assigned | ONVOY SPECTRUM, LLC | 624H | DETROITZN1 | MI |
| 2021-01-25 | 313-756-1XXX | 1000–1999 | Assigned | ONVOY SPECTRUM, LLC | 624H | DETROITZN1 | MI |
| 2020-11-18 | 313-756-2XXX | 2000–2999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - MI | 770E | DETROITZN1 | MI |
| 2020-11-18 | 313-756-3XXX | 3000–3999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - MI | 770E | DETROITZN1 | MI |
| 2020-11-18 | 313-756-4XXX | 4000–4999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - MI | 770E | DETROITZN1 | MI |
| 2020-11-18 | 313-756-5XXX | 5000–5999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - MI | 770E | DETROITZN1 | MI |
| 2020-12-16 | 313-756-6XXX | 6000–6999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MI | 6120 | DETROITZN1 | MI |
| 2021-09-29 | 313-756-7XXX | 7000–7999 | Assigned | ONVOY, LLCV - MI | 543C | DETROITZN1 | MI |
| 2021-01-25 | 313-756-8XXX | 8000–8999 | Assigned | 123.NET, LLC | 2550 | DETROITZN1 | MI |
| 2021-01-25 | 313-756-9XXX | 9000–9999 | Assigned | 123.NET, LLC | 2550 | DETROITZN1 | 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.