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
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2016-09-21 | 423-813-4XXX | 4000–4999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CLEVELAND | TN |
| 2014-12-05 | 423-777-9XXX | 9000–9999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CHATTNOOGA | TN |
| 2013-12-18 | 423-603-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | FORK RIDGE | TN |
| 2013-01-28 | 423-761-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | COPPERBSIN | TN |
| 2012-11-27 | 423-441-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CUMBERLDGP | TN |
| 2012-11-07 | 423-455-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | JELLICO | TN |
| 2011-10-21 | 423-347-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | ROGERSVL | TN |
| 2011-10-21 | 423-445-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SURGOINSVL | TN |
| 2011-10-21 | 423-973-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNEEDVILLE | TN |
| 2011-10-20 | 423-393-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | BULLS GAP | TN |
| 2011-10-20 | 423-781-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | ETOWAH | TN |
| 2011-08-17 | 423-228-9XXX | 9000–9999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SO PITTSBG | TN |
| 2011-08-17 | 423-454-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | DECATUR | TN |
| 2011-08-17 | 423-799-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SPRINGCITY | TN |
| 2011-08-17 | 423-815-4XXX | 4000–4999 | Assigned | AT&T ENTERPRISES, LLC | 516C | WHITWELL | TN |
| 2011-03-03 | 423-371-4XXX | 4000–4999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SWEETWATER | TN |
| 2010-06-07 | 423-545-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | MADISONVL | TN |
| 2010-03-18 | 423-375-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | BENTON | TN |
| 2010-03-12 | 423-453-2XXX | 2000–2999 | Assigned | AT&T ENTERPRISES, LLC | 516C | ATHENS | TN |
| 2010-03-12 | 423-665-0XXX | 0000–0999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CHARLESTON | TN |
| 2010-03-09 | 423-451-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SODDYDAISY | TN |
| 2010-03-09 | 423-464-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CLEVELAND | TN |
| 2010-03-09 | 423-529-8XXX | 8000–8999 | Assigned | AT&T ENTERPRISES, LLC | 516C | GEORGETOWN | TN |
| 2010-03-09 | 423-567-6XXX | 6000–6999 | Assigned | AT&T ENTERPRISES, LLC | 516C | DAYTON | TN |
| 2010-03-09 | 423-939-4XXX | 4000–4999 | Assigned | AT&T ENTERPRISES, LLC | 516C | JASPER | TN |
| 2010-01-06 | 423-771-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CHATTNOOGA | TN |
| 2009-11-10 | 423-248-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | NEWPORT | TN |
| 2009-09-28 | 423-352-6XXX | 6000–6999 | Assigned | AT&T ENTERPRISES, LLC | 516C | LAFOLLETTE | TN |
| 2009-06-15 | 423-254-2XXX | 2000–2999 | Assigned | AT&T ENTERPRISES, LLC | 516C | MORRISTOWN | 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.