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
— 410-627 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-628 9XXX which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
— 410-629 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 BERLIN MD
— 410-630 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 CHASE MD
— 410-631 3XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-632 6XXX7XXX8XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SNOW HILL MD
— 410-633 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-634 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → VERIZON MARYLAND, INC. 9212 RIDGELY MD
— 410-635 0XXX1XXX4XXX5XXX7XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 NEWWINDSOR MD
— 410-636 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BRYNPKLNCM MD
— 410-637 9XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-638 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BEL AIR MD
— 410-639 0XXX3XXX4XXX5XXX6XXX8XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 ROCK HALL MD
— 410-640 not yet reported which blocks → SPOK, INC. 6630 BALTIMORE MD
— 410-641 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BERLIN MD
— 410-642 4XXX5XXX7XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 PERRYVILLE MD
— 410-643 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 STEVENSVL MD
— 410-644 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-645 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 WOODLAWN MD
— 410-646 8XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-647 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SEVERNA PK MD
— 410-648 0XXX1XXX2XXX3XXX4XXX7XXX8XXX9XXX · 7 holders which blocks → VERIZON MARYLAND, INC. 9212 GALENA MD
— 410-649 9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 BALTIMORE MD
— 410-650 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 DUNDALK MD
— 410-651 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PRINCEANNE MD
— 410-652 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 BEL AIR MD
— 410-653 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 410-654 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 410-655 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 RANDALLSTN MD
— 410-657 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 PARKVILLE MD
— 410-658 not yet reported which blocks → ARMSTRONG TEL. CO. OF MARYLAND 0216 RISING SUN MD
— 410-659 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-661 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PARKVILLE MD
— 410-662 2XXX3XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-663 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PARKVILLE MD
— 410-664 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-665 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PARKVILLE MD
— 410-666 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
— 410-667 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
— 410-668 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PARKVILLE MD
— 410-669 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-670 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 EDGEWOOD MD
— 410-671 0XXX1XXX2XXX3XXX4XXX5XXX8XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 EDGEWOOD MD
— 410-672 9XXX which blocks → VERIZON MARYLAND, INC. 9212 ODENTON MD
— 410-673 0XXX3XXX4XXX6XXX8XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 PRESTON MD
— 410-674 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ODENTON MD
— 410-675 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-676 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 EDGEWOOD MD
— 410-677 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 SALISBURY MD
— 410-678 not yet reported which blocks → SPOK, INC. 6630 ELKRIDGE 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.