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 585
FRONTIER TELEPHONE OF ROCHESTER, INC. 69
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
2018-04-11 585-602-0XXX 0000–0999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-1XXX 1000–1999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-3XXX 3000–3999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-4XXX 4000–4999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-5XXX 5000–5999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-6XXX 6000–6999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-7XXX 7000–7999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-8XXX 8000–8999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2018-04-11 585-602-9XXX 9000–9999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2011-02-28 585-626-3XXX 3000–3999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 WEBSTER NY
2010-04-08 585-571-5XXX 5000–5999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 SCOTTSVL NY
2009-07-10 585-666-4XXX 4000–4999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2009-07-01 585-500-4XXX 4000–4999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2008-07-17 585-351-5XXX 5000–5999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2008-01-31 585-444-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 HENRIETTA NY
2008-01-24 585-294-8XXX 8000–8999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 CALEDONIA NY
2007-11-20 585-641-6XXX 6000–6999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 EROCHESTER NY
2007-09-19 585-627-9XXX 9000–9999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2007-06-27 585-678-7XXX 7000–7999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 FAIRPORT NY
2007-03-20 585-991-5XXX 5000–5999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 GENESEO NY
2006-11-08 585-869-3XXX 3000–3999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 VICTOR NY
2006-10-09 585-678-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 FAIRPORT NY
2006-09-21 585-384-4XXX 4000–4999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 COHOCTON NY
2006-07-31 585-302-3XXX 3000–3999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 PERRY NY
2006-07-31 585-347-7XXX 7000–7999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 W WEBSTER NY
2006-07-31 585-391-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 BROCKPORT NY
2006-07-31 585-412-7XXX 7000–7999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 CANANDAGUA NY
2006-07-31 585-487-5XXX 5000–5999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 HENRIETTA NY
2006-07-31 585-545-3XXX 3000–3999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 WEBSTER NY
2006-07-31 585-643-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 EROCHESTER NY
2006-07-31 585-991-4XXX 4000–4999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 GENESEO NY
2006-04-07 585-662-6XXX 6000–6999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 EROCHESTER NY
2005-09-06 585-398-5XXX 5000–5999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 VICTOR NY
2005-08-29 585-216-8XXX 8000–8999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 WEBSTER NY
2005-08-16 585-487-3XXX 3000–3999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 HENRIETTA NY
2005-05-18 585-753-0XXX 0000–0999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-1XXX 1000–1999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-3XXX 3000–3999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-4XXX 4000–4999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-5XXX 5000–5999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-6XXX 6000–6999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-7XXX 7000–7999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-8XXX 8000–8999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2005-05-18 585-753-9XXX 9000–9999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2004-12-06 585-487-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 HENRIETTA NY
2004-08-20 585-413-9XXX 9000–9999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 ROCHESTER NY
2004-03-31 585-267-1XXX 1000–1999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 EROCHESTER NY
2004-03-31 585-267-2XXX 2000–2999Assigned FRONTIER TELEPHONE OF ROCHESTER, INC. 0121 EROCHESTER NY

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.