NumberResearchThousands-blocks in 423-572
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 423-572 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 423 blocks
Most active assignees, all time — NPA 423
New assignments by month
Sep 2026
Aug 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 423-572-0XXX | 0000–0999 | Reserved | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| — | 423-572-1XXX | 1000–1999 | Reserved | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| — | 423-572-2XXX | 2000–2999 | Reserved | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-07-17 | 423-572-3XXX | 3000–3999 | Assigned | TERRA NOVA TELECOM INC. | 145J | ENGLEWOOD | TN |
| 2010-08-25 | 423-572-4XXX | 4000–4999 | Assigned | PAETEC ITEL, LLC | 829J | ENGLEWOOD | TN |
| 2025-04-30 | 423-572-5XXX | 5000–5999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2021-09-27 | 423-572-6XXX | 6000–6999 | Assigned | ONVOY, LLC - TN | 525E | ENGLEWOOD | TN |
| — | 423-572-7XXX | 7000–7999 | Available | ENGLEWOOD | TN | ||
| — | 423-572-8XXX | 8000–8999 | Available | ENGLEWOOD | TN | ||
| — | 423-572-9XXX | 9000–9999 | Available | ENGLEWOOD | TN |
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.