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
2013-08-12 443-354-9XXX 9000–9999Assigned IP HORIZON LLC 515J GLENBURNIE MD
2013-08-12 443-399-9XXX 9000–9999Assigned IP HORIZON LLC 515J DUNDALK MD
2013-08-12 443-456-0XXX 0000–0999Assigned IP HORIZON LLC 515J EDGEWOOD MD
2013-08-12 443-648-8XXX 8000–8999Assigned IP HORIZON LLC 515J ESSEX MD
2013-08-12 443-660-0XXX 0000–0999Assigned IP HORIZON LLC 515J PIKESVILLE MD
2013-08-12 443-734-0XXX 0000–0999Assigned IP HORIZON LLC 515J SEVERN MD
2013-08-12 443-784-0XXX 0000–0999Assigned IP HORIZON LLC 515J ARGRGBSNIS MD
2013-08-12 443-828-2XXX 2000–2999Assigned IP HORIZON LLC 515J ELLICOTTCY MD
2013-08-12 443-910-9XXX 9000–9999Assigned IP HORIZON LLC 515J BEL AIR MD
2013-08-12 443-917-0XXX 0000–0999Assigned IP HORIZON LLC 515J COLUMBIA MD
2013-08-06 443-981-3XXX 3000–3999Assigned COMCAST IP PHONE, LLC 318J FALLSTON MD
2013-08-05 443-402-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J EDGEWOOD MD
2013-08-05 443-699-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J ANNAPOLIS MD
2013-08-05 443-917-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J COLUMBIA MD
2013-07-30 443-607-4XXX 4000–4999Assigned COMCAST IP PHONE, LLC 318J WEST RIVER MD
2013-07-26 443-558-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ABERDEEN MD
2013-07-23 443-873-6XXX 6000–6999Assigned COMCAST IP PHONE, LLC 318J BALTIMORE MD
2013-07-23 443-873-7XXX 7000–7999Assigned COMCAST IP PHONE, LLC 318J BALTIMORE MD
2013-07-23 443-873-8XXX 8000–8999Assigned COMCAST IP PHONE, LLC 318J BALTIMORE MD
2013-07-23 443-873-9XXX 9000–9999Assigned COMCAST IP PHONE, LLC 318J BALTIMORE MD
2013-07-22 443-214-3XXX 3000–3999Assigned ONVOY, LLC - MD 876D ANNAPOLIS MD
2013-07-15 443-315-2XXX 2000–2999Assigned ONVOY, LLC - MD 876D CATONSVL MD
2013-07-12 443-784-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ARGRGBSNIS MD
2013-07-10 443-403-8XXX 8000–8999Assigned LEVEL 3 TELECOM OF MARYLAND, LLC - MD 7591 ABERDEEN MD
2013-07-05 443-450-3XXX 3000–3999Assigned COMCAST IP PHONE, LLC 318J PIKESVILLE MD
2013-07-02 443-297-2XXX 2000–2999Assigned METROPCS, INC. 5562 ARBUTUS MD
2013-07-02 443-297-4XXX 4000–4999Assigned METROPCS, INC. 5562 ARBUTUS MD
2013-07-02 443-979-1XXX 1000–1999Assigned METROPCS, INC. 5562 COLUMBIA MD
2013-07-02 443-991-6XXX 6000–6999Assigned METROPCS, INC. 5562 TOWSON MD
2013-06-27 443-736-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - MD 6119 SALISBURY MD
2013-06-27 443-832-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - MD 6119 COLUMBIA MD
2013-06-26 443-720-8XXX 8000–8999Assigned OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 ABERDEEN MD
2013-06-26 443-720-9XXX 9000–9999Assigned OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 ABERDEEN MD
2013-06-26 443-763-7XXX 7000–7999Assigned OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 GLENBURNIE MD
2013-06-25 443-294-6XXX 6000–6999Assigned COMCAST IP PHONE, LLC 318J WEST RIVER MD
2013-06-25 443-917-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 COLUMBIA MD
2013-06-21 443-410-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J GLENBURNIE MD
2013-06-17 443-214-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
2013-05-22 443-354-6XXX 6000–6999Assigned METROPCS, INC. 5562 GLENBURNIE MD
2013-05-22 443-354-7XXX 7000–7999Assigned METROPCS, INC. 5562 GLENBURNIE MD
2013-05-22 443-522-1XXX 1000–1999Assigned METROPCS, INC. 5562 REISTERSTN MD
2013-05-22 443-599-2XXX 2000–2999Assigned METROPCS, INC. 5562 SEVERN MD
2013-05-22 443-599-3XXX 3000–3999Assigned METROPCS, INC. 5562 SEVERN MD
2013-05-22 443-698-2XXX 2000–2999Assigned METROPCS, INC. 5562 ODENTON MD
2013-05-22 443-943-2XXX 2000–2999Assigned METROPCS, INC. 5562 SPARROWSPT MD
2013-05-22 443-943-3XXX 3000–3999Assigned METROPCS, INC. 5562 SPARROWSPT MD
2013-05-22 443-991-1XXX 1000–1999Assigned METROPCS, INC. 5562 TOWSON MD
2013-05-22 443-991-2XXX 2000–2999Assigned METROPCS, INC. 5562 TOWSON MD
2013-05-22 443-991-3XXX 3000–3999Assigned METROPCS, INC. 5562 TOWSON MD
2013-05-21 443-325-2XXX 2000–2999Assigned METROPCS, INC. 5562 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.