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
— 410-363 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 410-364 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 7 holders which blocks → VERIZON MARYLAND, INC. 9212 HILLSBORO MD
— 410-365 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BALTIMORE MD
— 410-366 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-367 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-368 0XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-369 6XXX8XXX which blocks → LEVEL 3 TELECOM OF MARYLAND, LLC - MD 7591 BALTIMORE MD
— 410-370 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-371 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-372 3XXX5XXX6XXX7XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
— 410-373 not yet reported which blocks → SPOK, INC. 6630 TOWSON MD
— 410-374 7XXX which blocks → VERIZON MARYLAND, INC. 9212 HAMPSTEAD MD
— 410-375 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-376 1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 VIENNA MD
— 410-377 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
— 410-378 7XXX which blocks → VERIZON MARYLAND, INC. 9212 PT DEPOSIT MD
— 410-379 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELKRIDGE MD
— 410-380 not yet reported which blocks → REDI-CALL COMMUNICATIONS CO. 6810 SALISBURY MD
— 410-381 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 410-382 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-383 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-384 3XXX4XXX6XXX8XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SEVERNA PK MD
— 410-385 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-386 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WESTMINSTR MD
— 410-388 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SPARROWSPT MD
— 410-389 not yet reported which blocks → SPOK, INC. 6630 BALTIMORE MD
— 410-391 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ESSEX MD
— 410-392 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELKTON MD
— 410-393 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-394 4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SOLOMONS MD
— 410-395 4XXX which blocks → VERIZON MARYLAND, INC. 9212 ARBUTUS MD
— 410-396 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-397 0XXX1XXX5XXX7XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 WINGATE MD
— 410-398 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELKTON MD
— 410-399 1XXX3XXX5XXX8XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 BEL AIR MD
— 410-401 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 BRYNPKLNCM MD
— 410-402 0XXX3XXX4XXX5XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 CATONSVL MD
— 410-403 0XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 COCKEYSVL MD
— 410-404 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-405 3XXX6XXX7XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 FORK MD
— 410-406 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 8 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 ESSEX MD
— 410-407 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELKRIDGE MD
— 410-408 not yet reported which blocks → SPOK, INC. 6630 TOWSON MD
— 410-409 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-411 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MD
— 410-412 0XXX3XXX4XXX5XXX6XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 GLENBURNIE MD
— 410-413 0XXX3XXX6XXX7XXX8XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 PIKESVILLE MD
— 410-414 6XXX which blocks → VERIZON MARYLAND, INC. 9212 PRINCEFRCK MD
— 410-415 1XXX3XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 410-416 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 WATERLO236 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.