NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

1 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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, last 30 days — NPA 517
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 1
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
Clear Download CSV ↓
Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 517-577 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J ADRIAN MI
— 517-579 1XXX2XXX3XXX5XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 HOWELL MI
— 517-580 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 LANSING MI
— 517-581 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 JACKSON MI
— 517-582 2XXX6XXX7XXX9XXX · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 LANSING MI
— 517-586 3XXX which blocks → PAETEC ITEL, LLC 829J HOWELL MI
— 517-589 1XXX4XXX6XXX7XXX · 4 holders which blocks → MICHIGAN BELL TEL CO 9323 LESLIE MI
— 517-592 not yet reported which blocks → FRONTIER COMMUNICATIONS OF MICHIGAN, INC. 4417 BROOKLYN MI
— 517-596 0XXX1XXX4XXX5XXX6XXX9XXX · 3 holders which blocks → FRONTIER MIDSTATES, INC. - MI 0681 MUNITH MI
— 517-599 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 LANSING MI
— 517-605 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 ADRIAN MI
— 517-606 not yet reported which blocks → TC3 TELECOM, INC. - MI 3459 BLISSFIELD MI
— 517-607 0XXX1XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → MICHIGAN BELL TEL CO 9323 HILLSDALE MI
— 517-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MI
— 517-617 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 COLDWATER MI
— 517-618 1XXX7XXX8XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 HOWELL MI
— 517-622 9XXX which blocks → FRONTIER NORTH, INC. - MI 0695 GRANDLEDGE MI
— 517-623 2XXX3XXX4XXX5XXX7XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 DANSVILLE MI
— 517-625 2XXX9XXX which blocks → SHIAWASSEE TEL. CO. 0726 PERRY MI
— 517-626 0XXX1XXX3XXX4XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - MI 0695 GRANDLEDGE MI
— 517-627 not yet reported which blocks → FRONTIER NORTH, INC. - MI 0695 GRANDLEDGE MI
— 517-628 0XXX1XXX4XXX5XXX6XXX7XXX9XXX · 6 holders which blocks → FRONTIER MIDSTATES, INC. - MI 0681 ONONDAGA MI
— 517-629 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 ALBION MI
— 517-630 1XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → MICHIGAN BELL TEL CO 9323 ALBION MI
— 517-639 0XXX1XXX2XXX6XXX · 3 holders which blocks → FRONTIER NORTH, INC. - MI 0695 QUINCY MI
— 517-641 0XXX1XXX2XXX3XXX5XXX9XXX · 6 holders which blocks → FRONTIER NORTH, INC. - MI 0695 BATH MI
— 517-645 3XXX5XXX6XXX8XXX · 2 holders which blocks → MICHIGAN BELL TEL CO 9323 POTTERVL MI
— 517-646 1XXX4XXX · 2 holders which blocks → MICHIGAN BELL TEL CO 9323 DIMONDALE MI
— 517-647 3XXX9XXX which blocks → MICHIGAN BELL TEL CO 9323 PORTLAND MI
— 517-648 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 LANSING MI
— 517-649 0XXX1XXX3XXX4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 MULLIKEN MI
— 517-651 0XXX4XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - MI 0695 LAINGSBURG MI
— 517-655 not yet reported which blocks → FRONTIER NORTH, INC. - MI 0695 WILLIAMSTN MI
— 517-657 0–9 XXXall 10 · 4 holders which blocks → COMCAST IP PHONE, LLC 318J LANSING MI
— 517-663 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 EATON RPD MI
— 517-664 0XXX3XXX9XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 LANSING MI
— 517-668 4XXX5XXX6XXX7XXX · 4 holders which blocks → FRONTIER NORTH, INC. - MI 0695 DE WITT MI
— 517-669 not yet reported which blocks → FRONTIER NORTH, INC. - MI 0695 DE WITT MI
— 517-675 8XXX9XXX which blocks → SHIAWASSEE TEL. CO. 0726 SHAFTSBURG MI
— 517-676 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 MASON MI
— 517-680 1XXX2XXX4XXX7XXX · 3 holders which blocks → FIRST COMMUNICATIONS, LLC 460K ALBION MI
— 517-688 not yet reported which blocks → FRONTIER COMMUNICATIONS OF MICHIGAN, INC. 4417 BUNDY HILL MI
— 517-694 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 HOLT MI
— 517-699 9XXX which blocks → MICHIGAN BELL TEL CO 9323 HOLT MI
— 517-700 not yet reported which blocks → MI
— 517-702 8XXX which blocks → MICHIGAN BELL TEL CO 9323 LANSING MI
— 517-703 3XXX4XXX6XXX7XXX · 2 holders which blocks → MICHIGAN BELL TEL CO 9323 LANSING MI
— 517-706 1XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 LANSING MI
— 517-711 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MI
— 517-719 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 LANSING MI

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.