NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/24/2026
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 251
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 |
|---|---|---|---|---|---|---|---|
| 2017-04-11 | 251-266-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | MOBILE | AL |
| 2016-03-30 | 251-439-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | MOBILE | AL |
| 2015-07-15 | 251-255-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | EVERGREEN | AL |
| 2014-09-30 | 251-270-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | FAIRHOPE | AL |
| 2013-11-08 | 251-241-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | BREWTON | AL |
| 2013-10-16 | 251-262-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | JACKSON | AL |
| 2013-04-12 | 251-299-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | MT VERNON | AL |
| 2012-12-18 | 251-406-8XXX | 8000–8999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | MOBILE | AL |
| 2011-12-14 | 251-288-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | MOBILE | AL |
| 2011-11-23 | 251-273-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | CITRONELLE | AL |
| 2010-10-20 | 251-239-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | BAYMINETTE | AL |
| 2009-04-09 | 251-287-9XXX | 9000–9999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AL | 7221 | MOBILE | AL |
| 2009-03-18 | 251-725-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | MOBILE | AL |
| 2003-08-12 | 251-243-9XXX | 9000–9999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | MOBILE | AL |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/24/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.