NumberResearchThousands-blocks in 301-278
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/20/2026
The ten 1,000-number thousand-blocks inside prefix 301-278 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 301 blocks
Most active assignees, all time — NPA 301
New assignments by month
Sep 2026
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Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2003-10-23 | 301-278-0XXX | 0000–0999 | Assigned | QUANTUM TELECOMMUNICATIONS, INC. - MD | 2596 | WSHNGTNZN5 | MD |
| 2013-05-20 | 301-278-1XXX | 1000–1999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | WSHNGTNZN5 | MD |
| 2014-02-27 | 301-278-2XXX | 2000–2999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | WSHNGTNZN5 | MD |
| 2004-02-26 | 301-278-3XXX | 3000–3999 | Assigned | CORE COMMUNICATIONS, INC.- MD | 2593 | WSHNGTNZN5 | MD |
| 2021-10-11 | 301-278-4XXX | 4000–4999 | Assigned | ONVOY SPECTRUM, LLC | 624H | WSHNGTNZN5 | MD |
| 2008-07-03 | 301-278-5XXX | 5000–5999 | Assigned | COMCAST IP PHONE, LLC | 318J | WSHNGTNZN5 | MD |
| 2015-08-20 | 301-278-6XXX | 6000–6999 | Assigned | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | WSHNGTNZN5 | MD |
| 2008-07-03 | 301-278-7XXX | 7000–7999 | Assigned | COMCAST IP PHONE, LLC | 318J | WSHNGTNZN5 | MD |
| 2010-05-28 | 301-278-8XXX | 8000–8999 | Assigned | BANDWIDTH.COM CLEC, LLC - MD | 071F | WSHNGTNZN5 | MD |
| — | 301-278-9XXX | 9000–9999 | Reserved | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | WSHNGTNZN5 | MD |
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.