NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/19/2026
Most carrier growth happens here, not at the prefix level: under number pooling, carriers receive individual 1,000-number blocks (e.g. 626-470-0XXX) within already-assigned prefixes. Assignments are initial assignments — the current serving carrier of individual numbers may differ due to portability.
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 |
|---|---|---|---|---|---|---|---|
| 2025-04-30 | 423-214-0XXX | 0000–0999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-214-6XXX | 6000–6999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-214-7XXX | 7000–7999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-214-8XXX | 8000–8999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-572-5XXX | 5000–5999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-606-2XXX | 2000–2999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-606-3XXX | 3000–3999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-606-4XXX | 4000–4999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-606-5XXX | 5000–5999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-606-7XXX | 7000–7999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-606-8XXX | 8000–8999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-606-9XXX | 9000–9999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-0XXX | 0000–0999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-1XXX | 1000–1999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-3XXX | 3000–3999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-4XXX | 4000–4999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-5XXX | 5000–5999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-6XXX | 6000–6999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-7XXX | 7000–7999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-8XXX | 8000–8999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-885-9XXX | 9000–9999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-887-1XXX | 1000–1999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-04-30 | 423-887-9XXX | 9000–9999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ENGLEWOOD | TN |
| 2025-01-13 | 423-377-2XXX | 2000–2999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | LAFOLLETTE | TN |
| 2025-01-13 | 423-449-3XXX | 3000–3999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | LAFOLLETTE | TN |
| 2025-01-13 | 423-449-4XXX | 4000–4999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | LAFOLLETTE | TN |
| 2025-01-13 | 423-449-5XXX | 5000–5999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | LAFOLLETTE | TN |
| 2025-01-13 | 423-449-6XXX | 6000–6999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | LAFOLLETTE | TN |
| 2016-03-22 | 423-701-1XXX | 1000–1999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ROBBINS | TN |
| 2014-02-06 | 423-701-0XXX | 0000–0999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ROBBINS | TN |
| 2007-12-24 | 423-801-0XXX | 0000–0999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | CUMBERLDGP | TN |
| 2007-06-27 | 423-252-9XXX | 9000–9999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ATHENS | TN |
| 2004-04-15 | 423-252-7XXX | 7000–7999 | Assigned | UNITED STATES CELLULAR - TN | 6278 | ATHENS | TN |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.