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
— 815-452 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 TOLUCA IL
— 815-453 0XXX1XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1036 ASHTON IL
— 815-454 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 SHEFFIELD IL
— 815-455 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 CRYSTAL LK IL
— 815-456 1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1036 FRANKLIGRV IL
— 815-457 0XXX1XXX4XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER COMMUNICATIONS OF THE CAROLINAS, INC - IL 1000 CISSNAPARK IL
— 815-458 1XXX5XXX8XXX · 3 holders which blocks → ILLINOIS BELL TEL CO 9329 BRAIDWOOD IL
— 815-459 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 CRYSTAL LK IL
— 815-460 not yet reported which blocks → FIRST COMMUNICATIONS, LLC 460K JOLIET IL
— 815-461 not yet reported which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 LOCKPORT IL
— 815-462 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 NEW LENOX IL
— 815-463 3XXX6XXX7XXX · 3 holders which blocks → ILLINOIS BELL TEL CO 9329 NEW LENOX IL
— 815-464 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 FRANKFORT IL
— 815-465 0XXX1XXX3XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → ILLINOIS BELL TEL CO 9329 GRANT PARK IL
— 815-466 4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → ILLINOIS BELL TEL CO 9329 GRANT PARK IL
— 815-467 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 MINOOKA IL
— 815-468 5XXX which blocks → ILLINOIS BELL TEL CO 9329 MANTENO IL
— 815-469 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 FRANKFORT IL
— 815-470 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-471 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 WATSEKA IL
— 815-472 1XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → ILLINOIS BELL TEL CO 9329 MOMENCE IL
— 815-473 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → FRONTIER COMMUNICATIONS OF THE CAROLINAS, INC - IL 1000 WOODLAND IL
— 815-474 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 JOLIET IL
— 815-475 0XXX2XXX3XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → ILLINOIS BELL TEL CO 9329 PLATTVILLE IL
— 815-476 3XXX8XXX which blocks → ILLINOIS BELL TEL CO 9329 WILMINGTON IL
— 815-477 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 CRYSTAL LK IL
— 815-478 2XXX8XXX · 2 holders which blocks → ILLINOIS BELL TEL CO 9329 MANHATTAN IL
— 815-479 3XXX4XXX which blocks → ILLINOIS BELL TEL CO 9329 CRYSTAL LK IL
— 815-481 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 LA GRANGE IL
— 815-482 none assigned yet which blocks → T-MOBILE USA, INC. 6529 WOODSTOCK IL
— 815-483 2XXX which blocks → T-MOBILE USA, INC. 6529 JOLIET IL
— 815-484 3XXX which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-485 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 NEW LENOX IL
— 815-486 0XXX1XXX2XXX3XXX4XXX5XXX6XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 DONOVAN IL
— 815-487 not yet reported which blocks → FIRST COMMUNICATIONS, LLC 460K PLAINFIELD IL
— 815-488 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 LA GRANGE IL
— 815-489 3XXX4XXX · 2 holders which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-490 not yet reported which blocks → ILLINOIS BELL TEL CO 9329 ROCKFORD IL
— 815-492 1XXX4XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1036 APPLERIVER IL
— 815-493 3XXX4XXX5XXX7XXX · 3 holders which blocks → CITIZENS TELECOM CO ILLINOIS-FRONTIER CITIZENS -IL 1183 LANARK IL
— 815-494 none assigned yet which blocks → UNITED STATES CELLULAR - IL 6265 ROCKFORD IL
— 815-495 0XXX1XXX5XXX6XXX7XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 LELAND IL
— 815-496 0XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 SHERIDAN IL
— 815-497 3XXX4XXX5XXX6XXX7XXX · 5 holders which blocks → FRONTIER NORTH, INC. - IL 1015 COMPTON IL
— 815-498 0XXX5XXX6XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - IL 1015 SOMONAUK IL
— 815-499 none assigned yet which blocks → UNITED STATES CELLULAR - IL 6265 STERLING IL
— 815-500 0XXX5XXX9XXX · 3 holders which blocks → MCC TELEPHONY LLC 593K MARSEILLES IL
— 815-501 0XXX2XXX which blocks → METROPCS, INC. 5562 DE KALB IL
— 815-502 not yet reported which blocks → FIRST COMMUNICATIONS, LLC 460K WOODSTOCK IL
— 815-503 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → METROPCS, INC. 5562 MENDOTA 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.