737
Area code

TX

United States geographic area code, in service since 2013-07-01. Part of the 512/737 overlay complex — ten-digit dialing required.

Split from 512. Overlaid with 512 .

Statusin service
Introduced2013-07-01
JurisdictionTX, US
Local dialing10D
Time zoneCentral
Last verified2026-09-17
Utilization 43.7% of assignable prefixes assigned As of 09/17/2026
0%346 of ~792 assignable NXX values (200–999 excl. N11)100%

Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2013-02-19, most recent 2026-09-16.

Area codes serve rate-center geographies, not municipal boundaries. “TX” identifies the jurisdiction, not an exact city footprint.

Top assignees

Ranked by assigned prefixes · initial assignee ≠ current carrier
Largest initial assignees in area code 737
RankAssigneePrefixesShare
01 ONVOY, LLC - TX 81 23.4%
02 T-MOBILE USA, INC. 33 9.5%
03 NEW CINGULAR WIRELESS PCS, LLC - IL 29 8.4%
04 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 28 8.1%
05 FRACTEL, LLC 26 7.5%
06 BANDWIDTH.COM CLEC, LLC - TX 21 6.1%
07 TELEPORT COMMUNICATIONS AMERICA, LLC - TX 13 3.8%
08 TON80 COMMUNICATIONS, LLC 9 2.6%
09 MULTIPLE OCN LISTING 9 2.6%
10 FOREMOST TELECOMMUNICATIONS CORPORATION - TX 7 2%

Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.

Change history

Recorded events for this NPA

Planning letters & orders

Primary documents
NANPA planning letters for area code 737
DateDocumentSubject
2012-08-01 PL-438 ↗ NPA 737 to Overlay NPA 512 (Texas)
2001-05-02 PL-276 ↗ Suspension of 512/737 NPA Relief (Texas)
2000-07-05 PL-233 ↗ NPA 737 to Overlay NPA 512 (Texas)

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