NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

WESTMINSTR prefixes in area code 443

NANPA records 15 assigned NXX blocks to rate center WESTMINSTR in area code 443, 1.9% of the 785 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 9 holders hold those blocks, the largest being CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD (4), NEW CINGULAR WIRELESS PCS, LLC - DC (2), LEVEL 3 COMMUNICATIONS, LLC - MD (2). The earliest assignment on record here is 2009-05-07 and the most recent 2011-09-07. 12 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area codes 351, 410, 419, 567 – overlay codes cover the same geography, so a rate center is served by all of them.

15 assigned blocks – 1.9% of 443
9 holders of record
12 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
443-201 AT&T NEW CINGULAR WIRELESS PCS, LLC - DC – yes yes
443-241 Onvoy ONVOY, LLC - MD – no yes
443-244 Lumen LEVEL 3 COMMUNICATIONS, LLC - MD – yes yes
443-289 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 2011-05-16 yes yes
443-293 Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD – yes yes
443-340 Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD – no yes
443-368 CORE COMMUNICATIONS, INC.- MD – no yes
443-487 Lumen LEVEL 3 COMMUNICATIONS, LLC - MD – yes yes
443-536 T-Mobile METROPCS, INC. – yes yes
443-547 Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 2009-05-07 yes yes
443-605 Windstream PAETEC ITEL, LLC – yes yes
443-789 AT&T NEW CINGULAR WIRELESS PCS, LLC - DC – yes yes
443-821 T-Mobile METROPCS, INC. 2010-07-13 yes yes
443-952 Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 2011-09-07 yes yes
443-974 AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - MD – yes yes

The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.

Who holds the blocks

HolderBrandBlocksShare here
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD Verizon 4 26.7%
NEW CINGULAR WIRELESS PCS, LLC - DC AT&T 2 13.3%
LEVEL 3 COMMUNICATIONS, LLC - MD Lumen 2 13.3%
METROPCS, INC. T-Mobile 2 13.3%
ONVOY, LLC - MD Onvoy 1 6.7%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD Verizon 1 6.7%
CORE COMMUNICATIONS, INC.- MD – 1 6.7%
PAETEC ITEL, LLC Windstream 1 6.7%
TELEPORT COMMUNICATIONS AMERICA, LLC - MD AT&T 1 6.7%

Same rate center in other codes

Overlay codes cover the same geography, so one rate center is served by all of them.

Frequently asked

Which prefixes belong to WESTMINSTR in area code 443?

15 blocks: 201, 241, 244, 289, 293, 340, 368, 487, 536, 547, 605, 789 and 3 more, all listed in the table above.

Which carriers have numbers in WESTMINSTR?

CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD (4 blocks), NEW CINGULAR WIRELESS PCS, LLC - DC (2 blocks), LEVEL 3 COMMUNICATIONS, LLC - MD (2 blocks), METROPCS, INC. (2 blocks), ONVOY, LLC - MD (1 block), MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is WESTMINSTR a city?

It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.

Other rate centers in 443

All 785 prefixes in 443