NumberResearch Membership · Data 09/19/2026

Recent thousands-block assignments

0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/19/2026

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, all time — NPA 520
LEVEL 3 COMMUNICATIONS, LLC - AZ 140
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
2024-11-01 520-641-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 BENSON AZ
2023-06-26 520-681-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 NOGALES AZ
2023-02-10 520-581-0XXX 0000–0999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TOMBSTONE AZ
2022-10-03 520-536-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 DOUGLAS AZ
2022-04-15 520-640-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2022-03-01 520-614-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-08-04 520-542-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-08-04 520-542-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-06-09 520-496-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-06-09 520-496-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-06-09 520-496-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-04-21 520-537-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-02-10 520-534-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-12-15 520-535-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-11-02 520-246-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-11-02 520-246-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-09-16 520-476-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-06-25 520-849-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-05-12 520-849-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-02-14 520-420-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-02-14 520-420-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2019-11-07 520-416-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2019-11-07 520-416-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2019-07-25 520-600-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2017-08-30 520-274-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2017-07-06 520-526-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2017-07-06 520-526-9XXX 9000–9999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2017-04-26 520-274-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2017-01-31 520-231-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 WHITLOW AZ
2016-09-21 520-274-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2016-05-02 520-200-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 HAYDEN AZ
2016-03-18 520-585-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2016-03-18 520-585-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2015-08-06 520-595-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 BENSON AZ
2015-08-06 520-635-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 CASAGRANDE AZ
2015-07-30 520-589-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2015-07-30 520-589-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2015-06-23 520-729-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-12-30 520-254-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 WILLCOX AZ
2014-11-18 520-213-8XXX 8000–8999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 CASAGRANDE AZ
2014-09-26 520-895-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 SIERRAVIST AZ
2014-09-12 520-257-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-09-12 520-257-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-09-12 520-257-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-08-07 520-448-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-08-07 520-448-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-07-01 520-422-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 BISBEE AZ
2014-06-06 520-447-1XXX 1000–1999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-06-06 520-447-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2014-04-17 520-447-2XXX 2000–2999Assigned LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.