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

LOCKHART prefixes in area code 512

NANPA records 11 assigned NXX blocks to rate center LOCKHART in area code 512, 1.4% 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. 7 holders hold those blocks, the largest being SOUTHWESTERN BELL (4), ONVOY, LLC - TX (2), LEVEL 3 COMMUNICATIONS, LLC - TX (1). The earliest assignment on record here is 2001-05-09 and the most recent 2022-05-04. 10 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 737, 864 – overlay codes cover the same geography, so a rate center is served by all of them.

11 assigned blocks – 1.4% of 512
7 holders of record
10 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
512-213 Lumen LEVEL 3 COMMUNICATIONS, LLC - TX 2003-02-11 yes yes
512-227 AT&T SOUTHWESTERN BELL 2001-05-09 yes yes
512-359 AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - TX 2010-01-11 yes yes
512-376 AT&T SOUTHWESTERN BELL – yes yes
512-398 AT&T SOUTHWESTERN BELL – no yes
512-620 AT&T SOUTHWESTERN BELL – yes yes
512-668 Charter TWC IP ENABLED SERVICES, LLC 2005-04-21 yes yes
512-729 Onvoy ONVOY, LLC - TX – yes yes
512-855 AT&T AT&T - LOCAL 2002-03-25 yes yes
512-885 Onvoy ONVOY, LLC - TX 2022-05-04 yes yes
512-995 AT&T NEW CINGULAR WIRELESS PCS, LLC - IL – 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
SOUTHWESTERN BELL AT&T 4 36.4%
ONVOY, LLC - TX Onvoy 2 18.2%
LEVEL 3 COMMUNICATIONS, LLC - TX Lumen 1 9.1%
TELEPORT COMMUNICATIONS AMERICA, LLC - TX AT&T 1 9.1%
TWC IP ENABLED SERVICES, LLC Charter 1 9.1%
AT&T - LOCAL AT&T 1 9.1%
NEW CINGULAR WIRELESS PCS, LLC - IL AT&T 1 9.1%

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 LOCKHART in area code 512?

11 blocks: 213, 227, 359, 376, 398, 620, 668, 729, 855, 885, 995. The table above gives the holder of each.

Which carriers have numbers in LOCKHART?

SOUTHWESTERN BELL (4 blocks), ONVOY, LLC - TX (2 blocks), LEVEL 3 COMMUNICATIONS, LLC - TX (1 block), TELEPORT COMMUNICATIONS AMERICA, LLC - TX (1 block), TWC IP ENABLED SERVICES, LLC (1 block), AT&T - LOCAL (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is LOCKHART 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 512

All 785 prefixes in 512