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

ESSEX prefixes in area code 443

NANPA records 14 assigned NXX blocks to rate center ESSEX in area code 443, 1.8% 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. 8 holders hold those blocks, the largest being PAETEC ITEL, LLC (4), TELEPORT COMMUNICATIONS AMERICA, LLC - MD (2), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (2). The earliest assignment on record here is 2001-05-11 and the most recent 2001-07-23. 14 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, 573, 667 – overlay codes cover the same geography, so a rate center is served by all of them.

14 assigned blocks – 1.8% of 443
8 holders of record
14 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
443-231 AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - MD – yes yes
443-460 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC – yes yes
443-505 Lumen LEVEL 3 COMMUNICATIONS, LLC - MD – yes yes
443-559 Comcast COMCAST IP PHONE, LLC – yes yes
443-579 Windstream PAETEC ITEL, LLC – yes yes
443-596 CORE COMMUNICATIONS, INC.- MD – yes yes
443-600 T-Mobile OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 2001-07-23 yes yes
443-648 AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - MD – yes yes
443-730 Windstream PAETEC ITEL, LLC – yes yes
443-772 Windstream PAETEC ITEL, LLC 2001-07-23 yes yes
443-777 Verizon VERIZON MARYLAND, INC. – yes yes
443-815 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC – yes yes
443-868 Verizon VERIZON MARYLAND, INC. – yes yes
443-969 Windstream PAETEC ITEL, LLC 2001-05-11 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
PAETEC ITEL, LLC Windstream 4 28.6%
TELEPORT COMMUNICATIONS AMERICA, LLC - MD AT&T 2 14.3%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC Verizon 2 14.3%
VERIZON MARYLAND, INC. Verizon 2 14.3%
LEVEL 3 COMMUNICATIONS, LLC - MD Lumen 1 7.1%
COMCAST IP PHONE, LLC Comcast 1 7.1%
CORE COMMUNICATIONS, INC.- MD – 1 7.1%
OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC T-Mobile 1 7.1%

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 ESSEX in area code 443?

14 blocks: 231, 460, 505, 559, 579, 596, 600, 648, 730, 772, 777, 815 and 2 more, all listed in the table above.

Which carriers have numbers in ESSEX?

PAETEC ITEL, LLC (4 blocks), TELEPORT COMMUNICATIONS AMERICA, LLC - MD (2 blocks), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (2 blocks), VERIZON MARYLAND, INC. (2 blocks), LEVEL 3 COMMUNICATIONS, LLC - MD (1 block), COMCAST IP PHONE, LLC (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is ESSEX 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