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
— 410-573 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ANNAPOLIS MD
— 410-574 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ESSEX MD
— 410-575 0XXX1XXX2XXX3XXX4XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 FORK MD
— 410-576 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-578 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-579 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELKRIDGE MD
— 410-580 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 410-581 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 410-582 1XXX2XXX3XXX6XXX7XXX8XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 GLENBURNIE MD
— 410-583 3XXX which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
— 410-584 3XXX5XXX which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
— 410-585 4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-586 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PRINCEFRCK MD
— 410-587 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ARBUTUS MD
— 410-588 6XXX7XXX9XXX which blocks → VERIZON MARYLAND, INC. 9212 BEL AIR MD
— 410-589 0XXX2XXX3XXX5XXX6XXX · 3 holders which blocks → LEVEL 3 TELECOM OF MARYLAND, LLC - MD 7591 BRYNPKLNCM MD
— 410-590 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 GLENBURNIE MD
— 410-591 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-592 1XXX4XXX which blocks → VERIZON MARYLAND, INC. 9212 FORK MD
— 410-593 0XXX1XXX3XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 FORK MD
— 410-594 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WOODLAWN MD
— 410-595 1XXX2XXX5XXX6XXX · 3 holders which blocks → LEVEL 3 TELECOM OF MARYLAND, LLC - MD 7591 GLENBURNIE MD
— 410-596 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WESTMINSTR MD
— 410-597 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WOODLAWN MD
— 410-598 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
— 410-599 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-601 3XXX which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-602 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 410-603 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 SALISBURY MD
— 410-604 4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 STEVENSVL MD
— 410-605 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-606 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WATERLO236 MD
— 410-607 not yet reported which blocks → SPOK, INC. 6630 TOWSON MD
— 410-608 none assigned yet which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-609 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 BRYNPKLNCM MD
— 410-610 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 PRINCEFRCK MD
— 410-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MD
— 410-612 3XXX which blocks → VERIZON MARYLAND, INC. 9212 EDGEWOOD MD
— 410-613 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-614 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-615 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CATONSVL MD
— 410-616 8XXX9XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 TOWSON MD
— 410-617 0XXX8XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-619 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 WATERLO236 MD
— 410-620 8XXX which blocks → VERIZON MARYLAND, INC. 9212 ELKTON MD
— 410-621 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 PRINCEANNE MD
— 410-623 0XXX1XXX3XXX4XXX5XXX6XXX7XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 MARION MD
— 410-624 2XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-625 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-626 none assigned yet which blocks → VERIZON MARYLAND, INC. 9212 ANNAPOLIS 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.