NumberResearchRecent thousands-block assignments
11 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/20/2026
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, last 30 days — NPA 331
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 |
|---|---|---|---|---|---|---|---|
| 2008-07-31 | 331-262-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2008-07-01 | 331-575-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2008-06-13 | 331-645-0XXX | 0000–0999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2008-06-13 | 331-645-1XXX | 1000–1999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2008-06-13 | 331-645-2XXX | 2000–2999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2008-06-13 | 331-645-3XXX | 3000–3999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2008-05-09 | 331-425-4XXX | 4000–4999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2008-05-09 | 331-425-5XXX | 5000–5999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2008-04-30 | 331-425-6XXX | 6000–6999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - IL | 6115 | AURORA | IL |
| 2008-04-30 | 331-425-7XXX | 7000–7999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - IL | 6115 | AURORA | IL |
| 2008-04-23 | 331-425-2XXX | 2000–2999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2008-04-23 | 331-425-3XXX | 3000–3999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2008-03-18 | 331-465-4XXX | 4000–4999 | Assigned | T-MOBILE USA, INC. | 6529 | W CHICAGO | IL |
| 2007-12-07 | 331-452-1XXX | 1000–1999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-12-06 | 331-456-0XXX | 0000–0999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-1XXX | 1000–1999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-2XXX | 2000–2999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-3XXX | 3000–3999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-4XXX | 4000–4999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-5XXX | 5000–5999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-6XXX | 6000–6999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-7XXX | 7000–7999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-8XXX | 8000–8999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-12-06 | 331-456-9XXX | 9000–9999 | Assigned | FIRST COMMUNICATIONS, LLC | 460K | ROSELLE | IL |
| 2007-11-15 | 331-452-3XXX | 3000–3999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-11-06 | 331-645-4XXX | 4000–4999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2007-11-06 | 331-645-5XXX | 5000–5999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2007-11-06 | 331-645-6XXX | 6000–6999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2007-11-06 | 331-645-7XXX | 7000–7999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2007-11-06 | 331-645-8XXX | 8000–8999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2007-11-06 | 331-645-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | ELMHURST | IL |
| 2007-10-05 | 331-452-5XXX | 5000–5999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-10-05 | 331-452-6XXX | 6000–6999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-10-05 | 331-452-7XXX | 7000–7999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-10-05 | 331-452-8XXX | 8000–8999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-09-21 | 331-452-0XXX | 0000–0999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-09-21 | 331-452-9XXX | 9000–9999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | AURORA | IL |
| 2007-09-21 | 331-643-0XXX | 0000–0999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-09-21 | 331-643-1XXX | 1000–1999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-09-21 | 331-643-2XXX | 2000–2999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-09-21 | 331-643-3XXX | 3000–3999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-09-21 | 331-643-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-08-24 | 331-684-0XXX | 0000–0999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - IL | 6115 | AURORA | IL |
| 2007-08-21 | 331-684-9XXX | 9000–9999 | Assigned | PAETEC ITEL, LLC | 829J | AURORA | IL |
| 2007-07-16 | 331-684-2XXX | 2000–2999 | Assigned | RCN TELECOM SERVICES OF ILLINIOS, INC. - IL | 8702 | AURORA | IL |
| 2007-07-12 | 331-425-0XXX | 0000–0999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-07-12 | 331-425-1XXX | 1000–1999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-07-12 | 331-425-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | AURORA | IL |
| 2007-07-11 | 331-248-0XXX | 0000–0999 | Assigned | COMCAST IP PHONE, LLC | 318J | GENEVA | IL |
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.