NumberResearch Membership · Data 09/21/2026

Recent thousands-block assignments

17 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/21/2026

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
2010-04-12 443-558-5XXX 5000–5999Assigned VERIZON MARYLAND, INC. 9212 ABERDEEN MD
2010-04-06 443-333-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
2010-04-05 443-478-6XXX 6000–6999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
2010-04-05 443-547-4XXX 4000–4999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WESTMINSTR MD
2010-04-05 443-736-6XXX 6000–6999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 SALISBURY MD
2010-03-30 443-422-2XXX 2000–2999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F GLENBURNIE MD
2010-03-30 443-470-3XXX 3000–3999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F TOWSON MD
2010-03-30 443-559-4XXX 4000–4999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F ESSEX MD
2010-03-17 443-204-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 PIKESVILLE MD
2010-03-17 443-518-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 COLUMBIA MD
2010-03-16 443-464-4XXX 4000–4999Assigned PAETEC ITEL, LLC 829J CHURCHVL MD
2010-03-16 443-464-5XXX 5000–5999Assigned PAETEC ITEL, LLC 829J CHURCHVL MD
2010-03-11 443-681-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BALTIMORE MD
2010-03-11 443-681-7XXX 7000–7999Assigned LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BALTIMORE MD
2010-03-09 443-518-7XXX 7000–7999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 COLUMBIA MD
2010-03-04 443-397-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 SALISBURY MD
2010-03-04 443-397-9XXX 9000–9999Assigned LEVEL 3 COMMUNICATIONS, LLC - MD 6119 SALISBURY MD
2010-03-04 443-547-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WESTMINSTR MD
2010-03-04 443-591-5XXX 5000–5999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 GLENBURNIE MD
2010-03-04 443-619-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BEL AIR MD
2010-03-04 443-684-3XXX 3000–3999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 PRINCEFRCK MD
2010-03-04 443-718-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 COLUMBIA MD
2010-03-04 443-761-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 TOWSON MD
2010-03-04 443-945-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 ELKTON MD
2010-02-25 443-873-2XXX 2000–2999Assigned ONVOY, LLC - MD 876D BALTIMORE MD
2010-02-24 443-760-3XXX 3000–3999Assigned PAETEC ITEL, LLC 829J ABERDEEN MD
2010-02-17 443-558-4XXX 4000–4999Assigned PAETEC ITEL, LLC 829J ABERDEEN MD
2010-02-11 443-345-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ABERDEEN MD
2010-02-08 443-396-3XXX 3000–3999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F ODENTON MD
2010-02-04 443-397-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 SALISBURY MD
2010-02-04 443-591-4XXX 4000–4999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 GLENBURNIE MD
2010-02-04 443-878-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 COLUMBIA MD
2010-02-04 443-966-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 FALLSTON MD
2010-02-02 443-478-3XXX 3000–3999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F BALTIMORE MD
2010-02-02 443-478-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BALTIMORE MD
2010-02-02 443-478-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BALTIMORE MD
2010-01-27 443-746-0XXX 0000–0999Assigned LEVEL 3 COMMUNICATIONS, LLC - MD 6119 EASTON MD
2010-01-26 443-212-8XXX 8000–8999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F SPARKSGLNC MD
2010-01-26 443-228-6XXX 6000–6999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F CHASE MD
2010-01-26 443-242-4XXX 4000–4999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F SPARROWSPT MD
2010-01-26 443-252-2XXX 2000–2999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F PERRYVILLE MD
2010-01-26 443-267-4XXX 4000–4999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F DARLINGTON MD
2010-01-26 443-300-6XXX 6000–6999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F SYKESVILLE MD
2010-01-26 443-304-7XXX 7000–7999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F ARBUTUS MD
2010-01-26 443-330-2XXX 2000–2999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F COCKEYSVL MD
2010-01-26 443-345-0XXX 0000–0999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F ABERDEEN MD
2010-01-26 443-380-0XXX 0000–0999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F WOODLAWN MD
2010-01-26 443-406-8XXX 8000–8999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F ELKTON MD
2010-01-26 443-420-7XXX 7000–7999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F ELLICOTTCY MD
2010-01-26 443-420-8XXX 8000–8999Assigned BANDWIDTH.COM CLEC, LLC - MD 071F ELLICOTTCY MD

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.