NumberResearch Membership · Data 09/20/2026

Recent thousands-block assignments

17 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/20/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

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 443
ONVOY, LLC - MD 8
NEW CINGULAR WIRELESS PCS, LLC - DC 4
VERSATEL LLC 1
OPENTACT INC. 1
LEVEL 3 COMMUNICATIONS, LLC - MD 1
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
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Recent thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
2018-05-24 443-727-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 BISHOPVL MD
2018-05-24 443-727-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 BISHOPVL MD
2018-05-23 443-222-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 WORTHINGTN MD
2018-05-23 443-222-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 WORTHINGTN MD
2018-05-23 443-222-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 WORTHINGTN MD
2018-05-23 443-238-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 PARKTON MD
2018-05-23 443-247-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 UNION BDG MD
2018-05-23 443-247-9XXX 9000–9999Assigned CORE COMMUNICATIONS, INC.- MD 2593 UNION BDG MD
2018-05-23 443-264-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 PIKESVILLE MD
2018-05-23 443-264-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 PIKESVILLE MD
2018-05-23 443-264-7XXX 7000–7999Assigned CORE COMMUNICATIONS, INC.- MD 2593 PIKESVILLE MD
2018-05-23 443-265-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 FORK MD
2018-05-23 443-265-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 FORK MD
2018-05-23 443-269-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 TOWSON MD
2018-05-23 443-269-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 TOWSON MD
2018-05-23 443-269-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 TOWSON MD
2018-05-23 443-284-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 WATERLO238 MD
2018-05-23 443-284-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 WATERLO238 MD
2018-05-23 443-337-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 SPARROWSPT MD
2018-05-23 443-337-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 SPARROWSPT MD
2018-05-23 443-337-7XXX 7000–7999Assigned CORE COMMUNICATIONS, INC.- MD 2593 SPARROWSPT MD
2018-05-23 443-343-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 MILLERSVL MD
2018-05-23 443-355-2XXX 2000–2999Assigned CORE COMMUNICATIONS, INC.- MD 2593 ELLICOTTCY MD
2018-05-23 443-363-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 SEVERN MD
2018-05-23 443-363-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 SEVERN MD
2018-05-23 443-431-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 RANDALLSTN MD
2018-05-23 443-431-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 RANDALLSTN MD
2018-05-23 443-431-7XXX 7000–7999Assigned CORE COMMUNICATIONS, INC.- MD 2593 RANDALLSTN MD
2018-05-23 443-502-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 HAVREGRACE MD
2018-05-23 443-549-8XXX 8000–8999Assigned CORE COMMUNICATIONS, INC.- MD 2593 DUNDALK MD
2018-05-23 443-582-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 CHURCHVL MD
2018-05-23 443-582-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 CHURCHVL MD
2018-05-23 443-592-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 ELKRIDGE MD
2018-05-23 443-592-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 ELKRIDGE MD
2018-05-23 443-592-7XXX 7000–7999Assigned CORE COMMUNICATIONS, INC.- MD 2593 ELKRIDGE MD
2018-05-23 443-628-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 GLENBURNIE MD
2018-05-23 443-628-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 GLENBURNIE MD
2018-05-23 443-628-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 GLENBURNIE MD
2018-05-23 443-644-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 JARRETTSVL MD
2018-05-23 443-644-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 JARRETTSVL MD
2018-05-23 443-647-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 NEWWINDSOR MD
2018-05-23 443-650-9XXX 9000–9999Assigned CORE COMMUNICATIONS, INC.- MD 2593 REISTERSTN MD
2018-05-23 443-662-2XXX 2000–2999Assigned CORE COMMUNICATIONS, INC.- MD 2593 SPARKSGLNC MD
2018-05-23 443-662-3XXX 3000–3999Assigned CORE COMMUNICATIONS, INC.- MD 2593 SPARKSGLNC MD
2018-05-23 443-674-4XXX 4000–4999Assigned CORE COMMUNICATIONS, INC.- MD 2593 NORTH EAST MD
2018-05-23 443-678-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 PARKVILLE MD
2018-05-23 443-678-7XXX 7000–7999Assigned CORE COMMUNICATIONS, INC.- MD 2593 PARKVILLE MD
2018-05-23 443-748-6XXX 6000–6999Assigned CORE COMMUNICATIONS, INC.- MD 2593 MILLERSVL MD
2018-05-23 443-748-7XXX 7000–7999Assigned CORE COMMUNICATIONS, INC.- MD 2593 MILLERSVL MD
2018-05-23 443-773-8XXX 8000–8999Assigned CORE COMMUNICATIONS, INC.- MD 2593 BRYNPKLNCM 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.