NumberResearch Membership · Data 09/24/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/24/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 309
FRONTIER NORTH, INC. - IL 99
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 NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2004-10-14 309-304 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 7 holders which blocks → FRONTIER NORTH, INC. - IL 1015 EUREKA IL
2002-10-16 309-851 none assigned yet which blocks → FRONTIER NORTH, INC. - IL 1015 KEWANEE IL
2001-05-21 309-770 7XXX which blocks → FRONTIER NORTH, INC. - IL 1015 WYOMING IL
2001-05-21 309-819 1XXX8XXX · 2 holders which blocks → FRONTIER NORTH, INC. - IL 1015 SUNNYLAND IL
2001-05-21 309-831 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
2001-05-21 309-866 1XXX2XXX3XXX6XXX7XXX8XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 MORTON IL
2001-03-20 309-622 0–9 XXXall 10 · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-243 0XXX3XXX4XXX6XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 DUNLAP IL
— 309-248 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 WASHBURN IL
— 309-249 0XXX1XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 EDELSTEIN IL
— 309-263 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 MORTON IL
— 309-266 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 MORTON IL
— 309-268 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-274 0XXX7XXX · 2 holders which blocks → FRONTIER NORTH, INC. - IL 1015 CHILLICOTH IL
— 309-284 9XXX which blocks → FRONTIER NORTH, INC. - IL 1015 MORTON IL
— 309-286 0XXX1XXX3XXX4XXX5XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 TOULON IL
— 309-288 0XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → FRONTIER NORTH, INC. - IL 1015 MINERAL IL
— 309-295 0XXX2XXX5XXX6XXX · 2 holders which blocks → FRONTIER NORTH, INC. - IL 1015 MACOMB IL
— 309-298 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 MACOMB IL
— 309-329 0XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 ASTORIA IL
— 309-359 0XXX1XXX2XXX7XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 MACKINAW IL
— 309-364 0XXX6XXX7XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 HENRY IL
— 309-365 1XXX4XXX6XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 LEXINGTON IL
— 309-376 1XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 CARLOCK IL
— 309-377 0XXX1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 CROPSEY IL
— 309-378 0XXX6XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 DOWNS IL
— 309-379 0XXX1XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 STANFORD IL
— 309-385 0XXX3XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 PRINCEVL IL
— 309-387 0XXX1XXX8XXX9XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 GROVELAND IL
— 309-392 4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 MINIERAGTN IL
— 309-394 0XXX3XXX4XXX6XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 BENSON IL
— 309-399 0XXX3XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 LA ROSE IL
— 309-432 0XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 MINONK IL
— 309-434 0XXX3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-436 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-438 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-443 0XXX2XXX3XXX4XXX8XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 LOW POINT IL
— 309-444 0XXX6XXX which blocks → FRONTIER NORTH, INC. - IL 1015 WASHINGTON IL
— 309-446 1XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 BRIMFIELD IL
— 309-449 0XXX1XXX2XXX7XXX8XXX9XXX · 6 holders which blocks → FRONTIER NORTH, INC. - IL 1015 HOPEDALE IL
— 309-451 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-452 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-454 not yet reported which blocks → FRONTIER NORTH, INC. - IL 1015 BLOOMINGTN IL
— 309-463 0XXX3XXX4XXX5XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 VARNA IL
— 309-467 1XXX8XXX · 2 holders which blocks → FRONTIER NORTH, INC. - IL 1015 EUREKA IL
— 309-469 0XXX4XXX6XXX7XXX8XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 SPARLAND IL
— 309-473 0XXX1XXX5XXX8XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 HEYWORTH IL
— 309-475 1XXX7XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 SAYBROOK IL
— 309-479 0XXX1XXX4XXX5XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 CASTLETON IL
— 309-493 8XXX which blocks → FRONTIER NORTH, INC. - IL 1015 CAMPGROVE IL

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/24/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.