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 240
OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 117
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 85
NEW CINGULAR WIRELESS PCS, LLC - DC 69
PAETEC ITEL, LLC 63
LEVEL 3 COMMUNICATIONS, LLC - MD 59
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
2018-12-21 240-564 0–9 XXXall 10 · 3 holders which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 LAUREL236 MD
2018-12-04 240-658 0–9 XXXall 10 · 4 holders which blocks → VONAGE AMERICA LLC 197D GAITHERSBG MD
2018-10-29 240-680 0–9 XXXall 10 · 2 holders which blocks → PEERLESS NETWORK OF MARYLAND, LLC 568G FREDERICK MD
2018-08-02 240-642 0–9 XXXall 10 · 5 holders which blocks → ADVANCED TELECOM SOLUTIONS, LLC 181J WSNGTNZN10 MD
2018-06-19 240-840 0–9 XXXall 10 · 5 holders which blocks → ONVOY SPECTRUM, LLC 624H FREDERICK MD
2018-06-12 240-648 0–9 XXXall 10 · 4 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 KEEDYSVL MD
2018-06-12 240-649 0–9 XXXall 10 · 3 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 SMITHSBURG MD
2018-06-11 240-596 0–9 XXXall 10 · 3 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 ASHTON236 MD
2018-06-11 240-598 0–9 XXXall 10 · 3 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 HUGHESVL MD
2018-06-11 240-610 0–9 XXXall 10 · 4 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 WSHNGTNZN4 MD
2018-06-11 240-622 0–9 XXXall 10 · 4 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 LA PLATA MD
2018-06-11 240-628 0–9 XXXall 10 · 5 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 MECHANCSVL MD
2018-06-11 240-634 0–9 XXXall 10 · 2 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 RIDGE MD
2018-06-11 240-635 0–9 XXXall 10 · 3 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 TOMPKINSVL MD
2018-06-11 240-637 0–9 XXXall 10 · 2 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 WSHNGTNZN3 MD
2018-06-11 240-647 0–9 XXXall 10 · 3 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 CLEAR SPG MD
2018-06-11 240-679 0–9 XXXall 10 · 4 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 FRIENDSVL MD
2018-06-01 240-639 0–9 XXXall 10 · 4 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 LAUREL236 MD
2018-05-15 240-594 0–9 XXXall 10 · 7 holders which blocks → BANDWIDTH.COM CLEC, LLC - MD 071F BITTINGER MD
2018-04-17 240-591 0–9 XXXall 10 · 8 holders which blocks → SHENTEL COMMUNICATIONS, LLC. - MD 836G HAGERSTOWN MD
2018-04-09 240-590 0–9 XXXall 10 · 5 holders which blocks → METROPCS, INC. 5562 WSNGTNZN12 MD
2018-03-07 240-589 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 MCCOOLE MD
2018-02-01 240-588 0–9 XXXall 10 · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 GRANTSVL MD
2018-01-11 240-521 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 LAUREL236 MD
2018-01-11 240-579 0–9 XXXwhole prefix which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 ASHTON236 MD
2018-01-11 240-584 0–9 XXXall 10 · 4 holders which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 LAUREL236 MD
2017-12-20 240-576 0–9 XXXall 10 · 3 holders which blocks → VONAGE AMERICA LLC 197D HAGERSTOWN MD
2017-12-18 240-655 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - MD 876D KITZMILLER MD
2017-11-15 240-572 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 LEONARDTN MD
2017-09-22 240-569 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - MD 071F FLINTSTONE MD
2017-09-15 240-537 0–9 XXXall 10 · 4 holders which blocks → ATLANTECH ONLINE, INC. - MD 361H HAGERSTOWN MD
2017-08-03 240-878 0–9 XXXall 10 · 5 holders which blocks → COMMIO, LLC 939H HAGERSTOWN MD
2017-07-05 240-563 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - MD 876D WSHNGTNZN5 MD
2017-06-20 240-867 0–9 XXXall 10 · 4 holders which blocks → COMMIO, LLC 939H WSHNGTNZN3 MD
2017-06-12 240-484 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 LAUREL236 MD
2017-05-18 240-267 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 HAGERSTOWN MD
2017-03-14 240-557 0–9 XXXall 10 · 5 holders which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 WSHNGTNZN6 MD
2017-03-07 240-531 0–9 XXXall 10 · 6 holders which blocks → TELNYX LLC 073H WSHNGTNZN3 MD
2017-01-09 240-665 0–9 XXXall 10 · 4 holders which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 WSNGTNZN10 MD
2016-11-10 240-690 0–9 XXXall 10 · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - DC 7529 GAITHERSBG MD
2016-10-20 240-918 0–9 XXXall 10 · 3 holders which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 ASHTON236 MD
2016-10-17 240-985 0XXX1XXX3XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J WILLIAMSPT MD
2016-10-17 240-996 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BRUNSWICK MD
2016-10-17 240-998 0–9 XXXall 10 · 6 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J HANCOCK MD
2016-10-05 240-540 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → THE VOICE APPLICATION NETWORK, LLC 507J WSNG238Z13 MD
2016-09-28 240-302 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 LAUREL236 MD
2016-09-02 240-451 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - MD 876D THURMONT MD
2016-09-02 240-862 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → ONVOY, LLC - MD 876D MT SAVAGE MD
2016-09-02 240-870 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → ONVOY, LLC - MD 876D MIDDLETOWN MD
2016-09-02 240-908 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - MD 876D WALKERSVL 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.