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
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
2009-05-21 301-225 0–9 XXXwhole prefix which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z14 MD
— 301-354 6XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNGTNZN10 MD
— 301-458 0XXX1XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN4 MD
— 301-539 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 LA PLATA MD
— 301-541 0XXX3XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN5 MD
— 301-542 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WALDORF MD
— 301-543 0XXX7XXX8XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 LAUREL236 MD
— 301-547 1XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN2 MD
— 301-556 3XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 GAITHERSBG MD
— 301-623 5XXX6XXX7XXX8XXX9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z13 MD
— 301-628 6XXX7XXX8XXX9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN3 MD
— 301-634 not yet reported which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN2 MD
— 301-658 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 ASHTON236 MD
— 301-666 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z14 MD
— 301-677 not yet reported which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z14 MD
— 301-679 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNGTNZN12 MD
— 301-683 4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN4 MD
— 301-684 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 INDIANHEAD MD
— 301-685 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 DAMASCS236 MD
— 301-691 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 POOLESVL MD
— 301-692 5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNGTNZN11 MD
— 301-715 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z15 MD
— 301-719 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNGTNZN16 MD
— 301-720 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 BRANDYWINE MD
— 301-747 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN6 MD
— 301-820 0XXX1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 GAITHERSBG MD
— 301-821 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 LAUREL236 MD
— 301-823 0–9 XXXall 10 · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z13 MD
— 301-828 0XXX1XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN2 MD
— 301-832 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN4 MD
— 301-833 0–9 XXXall 10 · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSNG236Z14 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.