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
2023-07-19 410-478 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 BALTIMORE MD
2023-05-17 410-410 0–9 XXXwhole prefix which blocks → ONVOY SPECTRUM, LLC 624H BALTIMORE MD
2020-01-08 410-210 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 GLENBURNIE MD
2019-06-04 410-936 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J SALISBURY MD
2015-11-19 410-826 0–9 XXXwhole prefix which blocks → ONVOY, LLC - MD 876D BALTIMORE MD
2012-01-27 410-934 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
2011-11-07 410-618 0–9 XXXall 10 · 5 holders which blocks → IDT AMERICA, CORP. - MD 228C PERRYVILLE MD
2011-10-06 410-240 0–9 XXXwhole prefix which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BALTIMORE MD
2011-10-06 410-301 0–9 XXXwhole prefix which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BALTIMORE MD
2011-09-30 410-220 0–9 XXXall 10 · 6 holders which blocks → METROPCS, INC. 5562 ELKRIDGE MD
2011-09-30 410-844 0–9 XXXall 10 · 2 holders which blocks → PEERLESS NETWORK OF MARYLAND, LLC 568G BALTIMORE MD
2011-08-25 410-805 0–9 XXXwhole prefix which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BALTIMORE MD
2011-08-12 410-387 0–9 XXXall 10 · 3 holders which blocks → PAETEC ITEL, LLC 829J BALTIMORE MD
2011-08-12 410-622 0–9 XXXall 10 · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 BALTIMORE MD
2010-06-23 410-973 0–9 XXXall 10 · 5 holders which blocks → MCC TELEPHONY OF THE MID-ATLANTIC, LLC - MD 861F BERLIN MD
2010-02-12 410-449 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - MD 071F SOLOMONS MD
2009-06-10 410-390 0–9 XXXall 10 · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 OCEAN CITY MD
2009-03-11 410-214 0–9 XXXall 10 · 5 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 RISING SUN MD
2008-05-30 410-656 0–9 XXXall 10 · 6 holders which blocks → ARMSTRONG TELECOMMUNICATIONS, INC. - MD 420C NORTH EAST MD
2008-05-13 410-929 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - MD 071F BALTIMORE MD
2007-08-16 410-417 0–9 XXXall 10 · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 EDGEWOOD MD
2006-07-31 410-660 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 ELKRIDGE MD
2006-06-15 410-400 0–9 XXXwhole prefix which blocks → PAETEC ITEL, LLC 829J BALTIMORE MD
2006-04-25 410-600 0–9 XXXall 10 · 7 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 BERLIN MD
2006-03-29 410-304 0–9 XXXall 10 · 7 holders which blocks → IDT AMERICA, CORP. - MD 228C QUEENSTOWN MD
2005-10-27 410-915 not yet reported which blocks → BALTIMORE-WASHINGTON TELEPHONE (BWT) 8697 BALTIMORE MD
2005-10-03 410-710 0–9 XXXall 10 · 2 holders which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BALTIMORE MD
2005-09-30 410-814 0–9 XXXall 10 · 3 holders which blocks → PAETEC ITEL, LLC 829J BALTIMORE MD
2005-06-28 410-470 0–9 XXXwhole prefix which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
2005-06-28 410-501 0–9 XXXall 10 · 5 holders which blocks → PAETEC ITEL, LLC 829J ARBUTUS MD
2005-05-10 410-577 0–9 XXXwhole prefix which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
2005-03-11 410-858 0–9 XXXall 10 · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 ANNAPOLIS MD
2005-02-10 410-870 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J PARKVILLE MD
2004-10-14 410-202 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 SALISBURY MD
2004-10-05 410-800 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 BALTIMORE MD
2004-10-04 410-900 0–9 XXXall 10 · 2 holders which blocks → PAETEC ITEL, LLC 829J BALTIMORE MD
2004-07-15 410-300 0–9 XXXwhole prefix which blocks → METROPCS, INC. 5562 ELKRIDGE MD
2004-05-27 410-200 0–9 XXXall 10 · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 7228 EASTON MD
2003-10-13 410-982 0–9 XXXall 10 · 4 holders which blocks → QUANTUM TELECOMMUNICATIONS, INC. - MD 2596 BALTIMORE MD
2003-06-09 410-999 0–9 XXXall 10 · 3 holders which blocks → BALTIMORE-WASHINGTON TELEPHONE (BWT) 8697 GLENBURNIE MD
2002-07-23 410-443 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 EASTON MD
2002-07-23 410-699 9XXX which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 CHESTERTN MD
2002-05-20 410-690 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 EASTON MD
2002-01-22 410-940 0–9 XXXall 10 · 4 holders which blocks → PAETEC ITEL, LLC 829J ANNAPOLIS MD
2001-08-21 410-941 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 JARRETTSVL MD
2001-04-18 410-845 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 SALISBURY MD
— 410-201 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 410-203 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ELLICOTTCY MD
— 410-204 0XXX1XXX2XXX3XXX4XXX5XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 ARBUTUS MD
— 410-205 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 PIKESVILLE 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.