NumberResearch Membership · Data 09/20/2026

Recent thousands-block assignments

11 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 331
ONVOY, LLC 6
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 3
NEW CINGULAR WIRELESS PCS, LLC - IL 1
BANDWIDTH.COM CLEC, LLC - IL 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
2014-01-14 331-888-3XXX 3000–3999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E WARRENVL IL
2013-12-26 331-305-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 NAPERVILLE IL
2013-11-29 331-216-7XXX 7000–7999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 OSWEGO IL
2013-11-25 331-210-6XXX 6000–6999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2013-11-25 331-251-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DOWNERSGRV IL
2013-11-22 331-240-0XXX 0000–0999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 W CHICAGO IL
2013-11-22 331-305-1XXX 1000–1999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2013-11-12 331-215-3XXX 3000–3999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2013-11-08 331-229-8XXX 8000–8999Assigned COMCAST IP PHONE, LLC 318J NAPERVILLE IL
2013-11-08 331-240-2XXX 2000–2999Assigned COMCAST IP PHONE, LLC 318J W CHICAGO IL
2013-11-08 331-777-4XXX 4000–4999Assigned COMCAST IP PHONE, LLC 318J DOWNERSGRV IL
2013-11-07 331-251-6XXX 6000–6999Assigned COMCAST IP PHONE, LLC 318J DOWNERSGRV IL
2013-10-25 331-702-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2013-10-25 331-702-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2013-10-25 331-702-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2013-10-25 331-703-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 W CHICAGO IL
2013-10-18 331-240-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 W CHICAGO IL
2013-10-18 331-240-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 W CHICAGO IL
2013-10-18 331-240-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 W CHICAGO IL
2013-10-18 331-240-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 W CHICAGO IL
2013-10-11 331-210-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2013-10-02 331-234-4XXX 4000–4999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 SUGARGROVE IL
2013-10-02 331-248-9XXX 9000–9999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E GENEVA IL
2013-10-01 331-210-9XXX 9000–9999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E ST CHARLES IL
2013-10-01 331-251-4XXX 4000–4999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 DOWNERSGRV IL
2013-10-01 331-251-5XXX 5000–5999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 DOWNERSGRV IL
2013-08-27 331-803-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 LEMONT IL
2013-08-27 331-803-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 LEMONT IL
2013-08-22 331-210-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2013-08-20 331-305-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2013-08-12 331-229-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2013-08-12 331-229-2XXX 2000–2999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2013-08-12 331-301-7XXX 7000–7999Assigned ONVOY, LLC 224C AURORA IL
2013-08-07 331-318-1XXX 1000–1999Assigned IP HORIZON LLC 515J LEMONT IL
2013-07-26 331-229-5XXX 5000–5999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 NAPERVILLE IL
2013-07-24 331-200-5XXX 5000–5999Assigned ONVOY, LLC 224C BARTLETT IL
2013-07-24 331-256-1XXX 1000–1999Assigned ONVOY, LLC 224C AURORA IL
2013-07-24 331-256-2XXX 2000–2999Assigned ONVOY, LLC 224C AURORA IL
2013-07-24 331-256-3XXX 3000–3999Assigned ONVOY, LLC 224C AURORA IL
2013-07-24 331-256-4XXX 4000–4999Assigned ONVOY, LLC 224C AURORA IL
2013-07-24 331-301-3XXX 3000–3999Assigned ONVOY, LLC 224C AURORA IL
2013-07-24 331-301-4XXX 4000–4999Assigned ONVOY, LLC 224C AURORA IL
2013-07-22 331-229-3XXX 3000–3999Assigned COMCAST IP PHONE, LLC 318J NAPERVILLE IL
2013-07-10 331-218-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 WHEATON IL
2013-07-10 331-218-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 WHEATON IL
2013-07-09 331-234-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 SUGARGROVE IL
2013-07-01 331-803-6XXX 6000–6999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 LEMONT IL
2013-06-25 331-777-2XXX 2000–2999Assigned COMCAST IP PHONE, LLC 318J DOWNERSGRV IL
2013-06-24 331-250-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2013-06-24 331-250-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 AURORA IL

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.