NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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 301
VERIZON MARYLAND, INC. 465
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 51
NEW CINGULAR WIRELESS PCS, LLC - DC 47
MCIMETRO ACCESS TRANSMISSION SERVICES LLC 40
TELEPORT COMMUNICATIONS AMERICA, LLC - DC 31
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
— 301-569 0–9 XXXall 10 · 6 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 GAITHERSBG MD
— 301-570 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ASHTON236 MD
— 301-571 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-572 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-573 none assigned yet which blocks → METROPCS, INC. 5562 HAGERSTOWN MD
— 301-574 6XXX7XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WSNG236Z15 MD
— 301-575 4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → PAETEC ITEL, LLC 829J LAUREL236 MD
— 301-576 not yet reported which blocks → PAETEC ITEL, LLC 829J WSHNGTNZN3 MD
— 301-577 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN4 MD
— 301-578 2XXX3XXX5XXX6XXX7XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-579 0XXX1XXX3XXX4XXX5XXX7XXX8XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 BRANDYWINE MD
— 301-580 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WSHNGTNZN3 MD
— 301-581 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-582 8XXX which blocks → VERIZON MARYLAND, INC. 9212 HAGERSTOWN MD
— 301-583 6XXX which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN4 MD
— 301-584 not yet reported which blocks → BALTIMORE-WASHINGTON TELEPHONE (BWT) 8697 WSNGTNZN12 MD
— 301-585 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-586 2XXX5XXX7XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-587 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-588 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-589 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-590 5XXX which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-591 6XXX7XXX · 2 holders which blocks → PAETEC ITEL, LLC 829J GAITHERSBG MD
— 301-592 7XXX which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-593 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-594 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN2 MD
— 301-595 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNG236Z13 MD
— 301-596 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 LAUREL238 MD
— 301-598 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN12 MD
— 301-599 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN5 MD
— 301-601 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-602 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 WSHNGTNZN3 MD
— 301-603 2XXX3XXX4XXX5XXX6XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN11 MD
— 301-604 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 LAUREL236 MD
— 301-605 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-606 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 FREDERICK MD
— 301-607 none assigned yet which blocks → VERIZON MARYLAND, INC. 9212 DAMASCS240 MD
— 301-608 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN3 MD
— 301-609 0XXX1XXX2XXX which blocks → VERIZON MARYLAND, INC. 9212 WALDORF MD
— 301-610 3XXX which blocks → VERIZON MARYLAND, INC. 9212 WSNGTNZN10 MD
— 301-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MD
— 301-613 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 WSHNGTNZN3 MD
— 301-614 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNG236Z13 MD
— 301-615 not yet reported which blocks → BANDWIDTH.COM CLEC, LLC - MD 071F WSNG236Z13 MD
— 301-616 none assigned yet which blocks → USCOC OF CUMBERLAND, INC. DBA UNITED STATES CEL MD 4720 OAKLAND MD
— 301-617 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 LAUREL236 MD
— 301-618 0XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WSHNGTNZN4 MD
— 301-619 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-620 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 FREDERICK MD
— 301-621 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WSNG238Z14 MD

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.