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
2013-06-24 331-250-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2013-06-24 331-250-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2013-06-21 331-803-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 LEMONT IL
2013-05-31 331-209-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J ELMHURST IL
2013-05-31 331-229-4XXX 4000–4999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J NAPERVILLE IL
2013-05-31 331-250-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J AURORA IL
2013-05-31 331-251-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J DOWNERSGRV IL
2013-05-31 331-803-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J LEMONT IL
2013-05-30 331-210-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J ST CHARLES IL
2013-05-29 331-200-6XXX 6000–6999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J BARTLETT IL
2013-05-21 331-245-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2013-05-21 331-245-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2013-05-06 331-214-9XXX 9000–9999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E DOWNERSGRV IL
2013-05-03 331-777-8XXX 8000–8999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 DOWNERSGRV IL
2013-05-02 331-215-4XXX 4000–4999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E NAPERVILLE IL
2013-05-02 331-215-7XXX 7000–7999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E NAPERVILLE IL
2013-04-29 331-281-0XXX 0000–0999Assigned COMCAST IP PHONE, LLC 318J NAPERVILLE IL
2013-04-29 331-803-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 LEMONT IL
2013-04-22 331-245-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2013-04-22 331-803-2XXX 2000–2999Assigned PAETEC ITEL, LLC 829J LEMONT IL
2013-04-12 331-240-3XXX 3000–3999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E W CHICAGO IL
2013-04-12 331-240-4XXX 4000–4999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E W CHICAGO IL
2013-04-12 331-803-4XXX 4000–4999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E LEMONT IL
2013-04-12 331-803-5XXX 5000–5999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E LEMONT IL
2013-04-09 331-209-1XXX 1000–1999Assigned IP HORIZON LLC 515J ELMHURST IL
2013-04-09 331-422-1XXX 1000–1999Assigned IP HORIZON LLC 515J ST CHARLES IL
2013-04-09 331-777-1XXX 1000–1999Assigned IP HORIZON LLC 515J DOWNERSGRV IL
2013-04-03 331-200-7XXX 7000–7999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E BARTLETT IL
2013-04-03 331-200-8XXX 8000–8999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E BARTLETT IL
2013-04-03 331-207-1XXX 1000–1999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E YORKVILLE IL
2013-04-03 331-207-9XXX 9000–9999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E YORKVILLE IL
2013-04-03 331-212-8XXX 8000–8999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E AURORA IL
2013-04-03 331-212-9XXX 9000–9999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E AURORA IL
2013-04-03 331-215-8XXX 8000–8999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E NAPERVILLE IL
2013-04-03 331-215-9XXX 9000–9999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E NAPERVILLE IL
2013-04-03 331-216-0XXX 0000–0999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E OSWEGO IL
2013-04-03 331-216-1XXX 1000–1999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E OSWEGO IL
2013-04-03 331-888-0XXX 0000–0999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E WARRENVL IL
2013-04-03 331-888-1XXX 1000–1999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E WARRENVL IL
2013-04-02 331-250-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2013-04-02 331-250-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2013-03-22 331-210-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2013-03-22 331-210-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2013-03-20 331-301-1XXX 1000–1999Assigned IP HORIZON LLC 515J AURORA IL
2013-03-19 331-281-1XXX 1000–1999Assigned ONVOY, LLC 224C NAPERVILLE IL
2013-03-12 331-215-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 NAPERVILLE IL
2013-02-21 331-251-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 DOWNERSGRV IL
2013-02-12 331-229-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2013-02-12 331-229-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2013-02-12 331-302-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 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.