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
2018-04-10 331-235-5XXX 5000–5999Assigned ONVOY, LLC 224C ST CHARLES IL
2018-03-28 331-227-6XXX 6000–6999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E SUGARGROVE IL
2018-03-28 331-227-7XXX 7000–7999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E SUGARGROVE IL
2018-03-28 331-227-9XXX 9000–9999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E SUGARGROVE IL
2018-03-26 331-237-0XXX 0000–0999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2018-03-08 331-255-6XXX 6000–6999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2018-02-23 331-235-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2018-02-23 331-237-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2018-02-23 331-237-9XXX 9000–9999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2018-02-09 331-238-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DOWNERSGRV IL
2018-02-07 331-238-1XXX 1000–1999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 DOWNERSGRV IL
2017-12-29 331-255-7XXX 7000–7999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2017-12-21 331-237-6XXX 6000–6999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 NAPERVILLE IL
2017-12-21 331-237-7XXX 7000–7999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 NAPERVILLE IL
2017-12-19 331-238-4XXX 4000–4999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 DOWNERSGRV IL
2017-12-19 331-238-5XXX 5000–5999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 DOWNERSGRV IL
2017-12-19 331-238-6XXX 6000–6999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 DOWNERSGRV IL
2017-12-18 331-757-3XXX 3000–3999Assigned ONVOY, LLC 224C LEMONT IL
2017-12-18 331-757-6XXX 6000–6999Assigned ONVOY, LLC 224C LEMONT IL
2017-12-04 331-237-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2017-11-09 331-244-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2017-11-08 331-237-1XXX 1000–1999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2017-11-08 331-237-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2017-11-08 331-237-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2017-11-08 331-237-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2017-11-02 331-231-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2017-11-02 331-231-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2017-10-25 331-230-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 AURORA IL
2017-10-25 331-233-2XXX 2000–2999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 DOWNERSGRV IL
2017-10-25 331-233-3XXX 3000–3999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 DOWNERSGRV IL
2017-10-23 331-231-4XXX 4000–4999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 NAPERVILLE IL
2017-10-16 331-230-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2017-10-11 331-236-7XXX 7000–7999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 WHEATON IL
2017-10-10 331-231-6XXX 6000–6999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 NAPERVILLE IL
2017-10-06 331-244-5XXX 5000–5999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-10-06 331-244-6XXX 6000–6999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-10-06 331-244-7XXX 7000–7999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-10-06 331-244-8XXX 8000–8999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-10-02 331-666-6XXX 6000–6999Assigned ONVOY, LLC 224C AURORA IL
2017-10-02 331-800-0XXX 0000–0999Assigned ONVOY, LLC 224C W CHICAGO IL
2017-10-02 331-800-8XXX 8000–8999Assigned ONVOY, LLC 224C W CHICAGO IL
2017-09-26 331-244-0XXX 0000–0999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-09-26 331-244-1XXX 1000–1999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-09-26 331-244-2XXX 2000–2999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-09-26 331-244-3XXX 3000–3999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-09-26 331-244-4XXX 4000–4999Assigned ONVOY, LLC 224C NAPERVILLE IL
2017-09-20 331-771-2XXX 2000–2999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 ST CHARLES IL
2017-09-15 331-315-1XXX 1000–1999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 LOMBARD IL
2017-09-15 331-315-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 LOMBARD IL
2017-09-13 331-233-7XXX 7000–7999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 DOWNERSGRV 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.