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 410
VERIZON MARYLAND, INC. 510
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 53
NEW CINGULAR WIRELESS PCS, LLC - DC 51
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 45
SPOK, INC. 28
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
— 410-418 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELLICOTTCY MD
— 410-419 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BALTIMORE MD
— 410-420 4XXX5XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BEL AIR MD
— 410-421 0XXX1XXX2XXX3XXX4XXX6XXX7XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SEVERNA PK MD
— 410-422 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 SALISBURY MD
— 410-423 not yet reported which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 COLUMBIA MD
— 410-424 0XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 GLENBURNIE MD
— 410-425 0XXX1XXX3XXX4XXX7XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 SMITH IS MD
— 410-426 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-427 not yet reported which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 TOWSON MD
— 410-428 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-429 0XXX1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 WORTHINGTN MD
— 410-430 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 SALISBURY MD
— 410-431 0XXX1XXX2XXX3XXX4XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SEVERNA PK MD
— 410-432 0XXX1XXX2XXX4XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SEVERNA PK MD
— 410-433 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-434 not yet reported which blocks → SPOK, INC. 6630 TOWSON MD
— 410-435 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-436 0XXX9XXX which blocks → VERIZON MARYLAND, INC. 9212 EDGEWOOD MD
— 410-437 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ARGRGBSNIS MD
— 410-438 0XXX1XXX4XXX6XXX7XXX8XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 SUDLERSVL MD
— 410-439 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ARGRGBSNIS MD
— 410-440 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-441 2XXX3XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ELKTON MD
— 410-442 6XXX which blocks → VERIZON MARYLAND, INC. 9212 ELLICOTTCY MD
— 410-444 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-445 not yet reported which blocks → SPOK, INC. 6630 BALTIMORE MD
— 410-446 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-447 not yet reported which blocks → SPOK, INC. 6630 COLUMBIA MD
— 410-448 8XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-450 3XXX4XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-451 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 CROFTON MD
— 410-452 1XXX2XXX3XXX4XXX6XXX7XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 CARDIFF MD
— 410-453 1XXX2XXX3XXX7XXX8XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
— 410-454 not yet reported which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 BALTIMORE MD
— 410-455 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 CATONSVL MD
— 410-456 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-457 1XXX3XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 DARLINGTON MD
— 410-458 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-459 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 FALLSTON MD
— 410-460 not yet reported which blocks → SPOK, INC. 6630 ELKRIDGE MD
— 410-461 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELLICOTTCY MD
— 410-462 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-463 none assigned yet which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 TRAPPE MD
— 410-464 7XXX8XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-465 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELLICOTTCY MD
— 410-466 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-467 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-468 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-469 0XXX1XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE 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.