NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

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 815
ILLINOIS BELL TEL CO 157
FRONTIER NORTH, INC. - IL 133
LEVEL 3 COMMUNICATIONS, LLC - IL 76
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 50
AERO NORTH COMMUNICATIONS, INC. - IL 43
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
— 815-343 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 OGLESBY IL
— 815-344 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 MCHENRY IL
— 815-345 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 WOODSTOCK IL
— 815-346 not yet reported which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 GARDNER IL
— 815-347 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 WOODSTOCK IL
— 815-349 1XXX3XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 MCHENRY IL
— 815-350 not yet reported which blocks → AERO NORTH COMMUNICATIONS, INC. - IL 443F FRANKLIGRV IL
— 815-351 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 KANKAKEE IL
— 815-352 7XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 KANKAKEE IL
— 815-353 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 WOODSTOCK IL
— 815-354 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 WOODSTOCK IL
— 815-355 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 WOODSTOCK IL
— 815-356 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 CRYSTAL LK IL
— 815-357 0XXX2XXX4XXX7XXX · 4 holders which blocks → ILLINOIS BELL TEL CO 9329 SENECA IL
— 815-358 not yet reported which blocks → C-R TELEPHONE CO. 1009 CORNELL IL
— 815-359 1XXX which blocks → BRIGHTSPEED OF ILLINOIS, LLC 1057 HARMON IL
— 815-360 not yet reported which blocks → AERO NORTH COMMUNICATIONS, INC. - IL 443F SUBLETTE IL
— 815-361 none assigned yet which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 MANHATTAN IL
— 815-362 0XXX1XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1036 GERMAN VLY IL
— 815-363 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 MCHENRY IL
— 815-364 7XXX8XXX9XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 MORRIS IL
— 815-365 1XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1015 REDDICK IL
— 815-366 6XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 OTTAWA IL
— 815-367 1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1036 WINSLOW IL
— 815-368 2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → FRONTIER NORTH, INC. - IL 1015 LOSTANT IL
— 815-369 0XXX1XXX6XXX7XXX8XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1036 LENA IL
— 815-370 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 KANKAKEE IL
— 815-371 8XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 UTICA IL
— 815-372 5XXX6XXX7XXX8XXX · 2 holders which blocks → ILLINOIS BELL TEL CO 9329 LOCKPORT IL
— 815-375 4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → UNITED STATES CELLULAR - IL 6265 DE KALB IL
— 815-376 1XXX3XXX6XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 OHIO IL
— 815-377 not yet reported which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CRESCENTCY IL
— 815-378 none assigned yet which blocks → T-MOBILE USA, INC. 6529 ROCKFORD IL
— 815-379 1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → FRONTIER NORTH, INC. - IL 1015 WALNUT IL
— 815-380 0XXX1XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 STERLING IL
— 815-381 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-382 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WOODSTOCK IL
— 815-383 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CRESCENTCY IL
— 815-384 0XXX1XXX2XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1036 CRESTON IL
— 815-385 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 MCHENRY IL
— 815-386 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 KANKAKEE IL
— 815-387 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-388 0–9 XXXall 10 · 7 holders which blocks → METROPCS, INC. 5562 MCHENRY IL
— 815-389 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 SO BELOIT IL
— 815-391 0XXX1XXX3XXX4XXX which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-392 not yet reported which blocks → KINSMAN MUTUAL TEL. CO. 1041 KINSMAN IL
— 815-393 1XXX2XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1036 MONROE CTR IL
— 815-394 9XXX which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-395 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-396 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - IL 1036 STEWARD IL

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.