NumberResearchThousands-blocks in 406-371
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 406-371 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 406 blocks
Most active assignees, last 30 days — NPA 406
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 |
|---|---|---|---|---|---|---|---|
| 2026-09-08 | 406-371-0XXX | 0000–0999 | Assigned | T-MOBILE USA, INC. | 6529 | BILLINGS | MT |
| 2006-05-26 | 406-371-1XXX | 1000–1999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | BILLINGS | MT |
| 2017-08-11 | 406-371-2XXX | 2000–2999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BILLINGS | MT |
| 2006-05-26 | 406-371-3XXX | 3000–3999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | BILLINGS | MT |
| 2013-08-20 | 406-371-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BILLINGS | MT |
| 2006-11-09 | 406-371-5XXX | 5000–5999 | Assigned | CHARTER IP ENABLED SERVICES, LLC | 792K | BILLINGS | MT |
| 2007-02-20 | 406-371-6XXX | 6000–6999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | BILLINGS | MT |
| 2014-04-18 | 406-371-7XXX | 7000–7999 | Assigned | CHARTER IP ENABLED SERVICES, LLC | 792K | BILLINGS | MT |
| 2006-06-14 | 406-371-8XXX | 8000–8999 | Assigned | QWEST CORPORATION | 9636 | BILLINGS | MT |
| 2004-08-13 | 406-371-9XXX | 9000–9999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BILLINGS | MT |
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.