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 301
VERIZON MARYLAND, INC. 465
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 51
NEW CINGULAR WIRELESS PCS, LLC - DC 47
MCIMETRO ACCESS TRANSMISSION SERVICES LLC 40
TELEPORT COMMUNICATIONS AMERICA, LLC - DC 31
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
— 301-622 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-623 5XXX6XXX7XXX8XXX9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z13 MD
— 301-624 0XXX3XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-625 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-626 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-627 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNG236Z15 MD
— 301-628 6XXX7XXX8XXX9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN3 MD
— 301-629 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → VERIZON MARYLAND, INC. 9212 WSNG238Z14 MD
— 301-630 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN6 MD
— 301-631 4XXX which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-632 0XXX1XXX which blocks → VERIZON MARYLAND, INC. 9212 WALDORF MD
— 301-633 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN2 MD
— 301-634 not yet reported which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN2 MD
— 301-636 0XXX3XXX4XXX5XXX7XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN5 MD
— 301-637 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WSNGTNZN10 MD
— 301-638 6XXX8XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WALDORF MD
— 301-639 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 FREDERICK MD
— 301-640 0XXX1XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-641 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WSHNGTNZN3 MD
— 301-642 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN2 MD
— 301-643 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WALDORF MD
— 301-644 0XXX which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-645 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WALDORF MD
— 301-646 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN2 MD
— 301-647 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 WSNG236Z13 MD
— 301-648 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN2 MD
— 301-649 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN11 MD
— 301-650 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-651 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WSHNGTNZN3 MD
— 301-652 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-653 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WALDORF MD
— 301-654 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-655 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN2 MD
— 301-656 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-657 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-658 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 ASHTON236 MD
— 301-659 8XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WALDORF MD
— 301-661 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN2 MD
— 301-662 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-663 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-664 0XXX1XXX2XXX3XXX4XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-665 0XXX6XXX7XXX8XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 HAGERSTOWN MD
— 301-666 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z14 MD
— 301-667 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 MYERSVILLE MD
— 301-668 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-669 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN5 MD
— 301-670 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-671 not yet reported which blocks → BANDWIDTH.COM CLEC, LLC - MD 071F HAGERSTOWN MD
— 301-672 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 LXTNPKGRML MD
— 301-673 0XXX1XXX3XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 FREDERICK MD

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.