NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 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, 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
— 301-512 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WSHNGTNZN3 MD
— 301-513 2XXX4XXX8XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WSNG236Z13 MD
— 301-514 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 FREDERICK MD
— 301-515 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 GAITHERSBG MD
— 301-516 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN5 MD
— 301-517 6XXX7XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-518 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WSHNGTNZN3 MD
— 301-519 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 GAITHERSBG MD
— 301-520 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WSHNGTNZN3 MD
— 301-521 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN6 MD
— 301-522 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN11 MD
— 301-523 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 WSHNGTNZN3 MD
— 301-524 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 FREDERICK MD
— 301-526 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN3 MD
— 301-527 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 GAITHERSBG MD
— 301-528 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 GAITHERSBG MD
— 301-529 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSNGTNZN10 MD
— 301-530 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-531 0XXX4XXX5XXX9XXX · 3 holders which blocks → STARPOWER COMMUNICATIONS, LLC - MD 8832 WSHNGTNZN4 MD
— 301-533 5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 OAKLAND MD
— 301-535 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WALDORF MD
— 301-536 9XXX which blocks → METROPCS, INC. 5562 LEONARDTN MD
— 301-537 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 WSHNGTNZN3 MD
— 301-538 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WSHNGTNZN2 MD
— 301-539 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 LA PLATA MD
— 301-540 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 GAITHERSBG 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
— 301-544 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-545 2XXX3XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-547 1XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 WSHNGTNZN2 MD
— 301-548 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-549 0XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 ASHTON236 MD
— 301-551 not yet reported which blocks → BALTIMORE-WASHINGTON TELEPHONE (BWT) 8697 WSHNGTNZN3 MD
— 301-552 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNG236Z13 MD
— 301-553 not yet reported which blocks → SPOK, INC. 6630 WALDORF MD
— 301-554 not yet reported which blocks → SPOK, INC. 6630 WSHNGTNZN2 MD
— 301-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST MD
— 301-556 3XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 GAITHERSBG MD
— 301-559 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN4 MD
— 301-560 not yet reported which blocks → PAETEC ITEL, LLC 829J WSHNGTNZN4 MD
— 301-561 not yet reported which blocks → BALTIMORE-WASHINGTON TELEPHONE (BWT) 8697 WSHNGTNZN3 MD
— 301-562 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-563 9XXX which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-564 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-565 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-566 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNG236Z13 MD
— 301-567 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN6 MD
— 301-568 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN5 MD

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.