NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/26/2026
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 301
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 |
|---|---|---|---|---|---|---|---|
| 2023-02-07 | 301-726-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | KITZMILLER | MD |
| 2019-09-03 | 301-835-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | FREDERICK | MD |
| 2015-07-09 | 301-732-8XXX | 8000–8999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | FREDERICK | MD |
| 2009-08-24 | 301-501-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | OAKLAND | MD |
| 2009-08-24 | 301-969-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | BRUNSWICK | MD |
| 2009-08-21 | 301-304-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | WALKERSVL | MD |
| 2007-11-14 | 301-327-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | WSNG238Z15 | MD |
| 2006-02-14 | 301-302-8XXX | 8000–8999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | HAGERSTOWN | MD |
| 2006-02-14 | 301-723-7XXX | 7000–7999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | CUMBERLAND | MD |
| 2004-08-18 | 301-810-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | BUCKEYSTN | MD |
| 2004-07-30 | 301-712-9XXX | 9000–9999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | FREDERICK | MD |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/26/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.