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
— 410-523 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-524 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 OCEAN CITY MD
— 410-525 4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-526 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 REISTERSTN MD
— 410-527 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
— 410-528 3XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-529 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PARKVILLE MD
— 410-530 none assigned yet which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-531 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 410-532 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-533 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
— 410-534 9XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-535 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PRINCEFRCK MD
— 410-536 2XXX3XXX6XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 ARBUTUS MD
— 410-537 0XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-538 0XXX1XXX2XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 FORK MD
— 410-539 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-540 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELKRIDGE MD
— 410-541 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 SEVERNA PK MD
— 410-542 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-543 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SALISBURY MD
— 410-544 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SEVERNA PK MD
— 410-545 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-546 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SALISBURY MD
— 410-547 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-548 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SALISBURY MD
— 410-549 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SYKESVILLE MD
— 410-550 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-551 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SEVERN MD
— 410-552 7XXX8XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 SYKESVILLE MD
— 410-553 1XXX4XXX5XXX7XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 GLENBURNIE MD
— 410-554 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST MD
— 410-556 0XXX2XXX5XXX7XXX8XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 CHURCHHILL MD
— 410-557 1XXX2XXX3XXX5XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 FORK MD
— 410-558 6XXX7XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-559 1XXX4XXX6XXX7XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 PIKESVILLE MD
— 410-560 8XXX which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
— 410-561 6XXX which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
— 410-562 none assigned yet which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
— 410-563 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-564 1XXX3XXX4XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ELKRIDGE MD
— 410-565 2XXX5XXX6XXX8XXX · 4 holders which blocks → LEVEL 3 TELECOM OF MARYLAND, LLC - MD 7591 ARBUTUS MD
— 410-566 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-567 0XXX3XXX4XXX5XXX6XXX7XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 ELKRIDGE MD
— 410-568 5XXX7XXX8XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 COCKEYSVL MD
— 410-569 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 EDGEWOOD MD
— 410-570 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
— 410-571 3XXX4XXX5XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 ANNAPOLIS MD
— 410-572 1XXX4XXX7XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SALISBURY 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.