Recent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026
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.
| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| 2023-11-21 | 443-443 | 0–9 XXXall 10 · 2 holders which blocks → | COMMIO, LLC | 939H | ARBUTUS | MD |
| 2023-05-16 | 443-667 | 0–9 XXXall 10 · 2 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | DELMAR | MD |
| 2018-11-19 | 443-774 | 0–9 XXXall 10 · 3 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | COLUMBIA | MD |
| 2017-02-23 | 443-936 | 0–9 XXXall 10 · 5 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | ELKRIDGE | MD |
| 2015-01-21 | 443-819 | 0–9 XXXall 10 · 5 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BEL AIR | MD |
| 2014-12-23 | 443-961 | 0–9 XXXall 10 · 3 holders which blocks → | INTRADO COMMUNICATIONS, LLC | 820C | BALTIMORE | MD |
| 2014-10-08 | 443-775 | 0–9 XXXall 10 · 7 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | ANNAPOLIS | MD |
| 2014-06-13 | 443-809 | 0–9 XXXwhole prefix which blocks → | LEVEL 3 COMMUNICATIONS, LLC - MD | 6119 | TOWSON | MD |
| 2014-04-04 | 443-808 | 0–9 XXXall 10 · 4 holders which blocks → | BANDWIDTH.COM CLEC, LLC - MD | 071F | ANNAPOLIS | MD |
| 2014-01-17 | 443-776 | 0–9 XXXall 10 · 7 holders which blocks → | BANDWIDTH.COM CLEC, LLC - MD | 071F | ELKRIDGE | MD |
| 2013-06-21 | 443-410 | 0–9 XXXall 10 · 5 holders which blocks → | CENTURYLINK COMMUNICATIONS, LLC | 508J | GLENBURNIE | MD |
| 2013-01-21 | 443-836 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BALTIMORE | MD |
| 2012-11-27 | 443-720 | 0–9 XXXall 10 · 4 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | ABERDEEN | MD |
| 2012-09-20 | 443-906 | 0–9 XXXall 10 · 5 holders which blocks → | PEERLESS NETWORK OF MARYLAND, LLC | 568G | SEVERNA PK | MD |
| 2012-09-19 | 443-713 | 0–9 XXXall 10 · 3 holders which blocks → | PEERLESS NETWORK OF MARYLAND, LLC | 568G | GLENBURNIE | MD |
| 2012-05-23 | 443-666 | 0–9 XXXall 10 · 9 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - MD | 6119 | CHESTERTN | MD |
| 2012-05-23 | 443-900 | 0–9 XXXwhole prefix which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | TOWSON | MD |
| 2012-04-05 | 443-301 | 0–9 XXXall 10 · 2 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BALTIMORE | MD |
| 2012-01-27 | 443-240 | 0–9 XXXwhole prefix which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BALTIMORE | MD |
| 2012-01-09 | 443-202 | 0–9 XXXwhole prefix which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | BALTIMORE | MD |
| 2011-12-06 | 443-571 | 0–9 XXXwhole prefix which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | BALTIMORE | MD |
| 2011-12-01 | 443-991 | 0–9 XXXall 10 · 5 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | TOWSON | MD |
| 2011-11-21 | 443-970 | 0–9 XXXwhole prefix which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | BALTIMORE | MD |
| 2011-11-21 | 443-972 | 0–9 XXXall 10 · 8 holders which blocks → | PAETEC ITEL, LLC | 829J | CAMBRIDGE | MD |
| 2011-11-21 | 443-978 | 0–9 XXXall 10 · 7 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | SALISBURY | MD |
| 2011-11-21 | 443-979 | 0–9 XXXall 10 · 4 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | COLUMBIA | MD |
| 2011-11-21 | 443-981 | 0–9 XXXall 10 · 5 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | FALLSTON | MD |
| 2011-11-09 | 443-634 | 0–9 XXXwhole prefix which blocks → | VERIZON MARYLAND, INC. | 9212 | WATERLO236 | MD |
| 2011-10-24 | 443-931 | 0–9 XXXall 10 · 4 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD | 7228 | BALTIMORE | MD |
| 2011-10-17 | 443-401 | 0–9 XXXwhole prefix which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | BALTIMORE | MD |
| 2011-10-11 | 443-214 | 0–9 XXXall 10 · 6 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | ANNAPOLIS | MD |
| 2011-10-07 | 443-862 | 0–9 XXXwhole prefix which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | TOWSON | MD |
| 2011-10-07 | 443-917 | 0–9 XXXall 10 · 8 holders which blocks → | ONVOY, LLC - MD | 876D | COLUMBIA | MD |
| 2011-10-07 | 443-960 | 0–9 XXXall 10 · 4 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | GLENBURNIE | MD |
| 2011-10-06 | 443-723 | 0–9 XXXall 10 · 2 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BALTIMORE | MD |
| 2011-10-06 | 443-726 | 0–9 XXXall 10 · 3 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BALTIMORE | MD |
| 2011-09-30 | 443-210 | 0–9 XXXall 10 · 6 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | SALISBURY | MD |
| 2011-09-07 | 443-903 | 0–9 XXXall 10 · 4 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | BEL AIR | MD |
| 2011-09-07 | 443-915 | 0–9 XXXwhole prefix which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | BALTIMORE | MD |
| 2011-09-07 | 443-941 | 0–9 XXXall 10 · 8 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | ELKTON | MD |
| 2011-09-07 | 443-952 | 0–9 XXXall 10 · 6 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | WESTMINSTR | MD |
| 2011-09-07 | 443-953 | 0–9 XXXall 10 · 3 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | SALISBURY | MD |
| 2011-08-25 | 443-580 | 0–9 XXXall 10 · 2 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BALTIMORE | MD |
| 2011-08-22 | 443-916 | 0–9 XXXall 10 · 2 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BALTIMORE | MD |
| 2011-08-22 | 443-932 | 0–9 XXXall 10 · 2 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BALTIMORE | MD |
| 2011-08-22 | 443-948 | 0–9 XXXall 10 · 5 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BALTIMORE | MD |
| 2011-08-11 | 443-892 | 0–9 XXXall 10 · 5 holders which blocks → | BANDWIDTH.COM CLEC, LLC - MD | 071F | NEWWINDSOR | MD |
| 2011-08-10 | 443-699 | 0–9 XXXall 10 · 4 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | ANNAPOLIS | MD |
| 2011-08-10 | 443-890 | 0–9 XXXall 10 · 2 holders which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 6395 | BALTIMORE | MD |
| 2011-07-18 | 443-560 | 0–9 XXXall 10 · 2 holders which blocks → | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 6855 | BALTIMORE | 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.