NumberResearchThousands-blocks in 571-491
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 571-491 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 571 blocks
Most active assignees, all time — NPA 571
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 |
|---|---|---|---|---|---|---|---|
| 2024-08-13 | 571-491-0XXX | 0000–0999 | Assigned | TERRA NOVA TELECOM INC. | 145J | DULLES | VA |
| 2024-01-11 | 571-491-1XXX | 1000–1999 | Assigned | TERRA NOVA TELECOM INC. | 145J | DULLES | VA |
| 2018-06-22 | 571-491-2XXX | 2000–2999 | Assigned | METROPCS, INC. | 5562 | DULLES | VA |
| 2024-11-27 | 571-491-3XXX | 3000–3999 | Assigned | IP HORIZON LLC | 515J | DULLES | VA |
| 2019-05-01 | 571-491-4XXX | 4000–4999 | Assigned | BANDWIDTH.COM CLEC, LLC - VA | 079F | DULLES | VA |
| 2019-07-11 | 571-491-5XXX | 5000–5999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | DULLES | VA |
| 2019-06-11 | 571-491-6XXX | 6000–6999 | Assigned | PEERLESS NETWORK OF VIRGINIA, LLC - VA | 275G | DULLES | VA |
| 2019-04-10 | 571-491-7XXX | 7000–7999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | DULLES | VA |
| 2019-03-19 | 571-491-8XXX | 8000–8999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - VA | 8825 | DULLES | VA |
| 2017-09-27 | 571-491-9XXX | 9000–9999 | Assigned | METROPCS, INC. | 5562 | DULLES | VA |
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.