Area Code 621

Texas

Area code 621 serves Texas, primarily Houston, in the Central Time (CT) time zone. It is an overlay area code sharing territory with area code 713.

Published:

Overlay Area Code

This area code is part of an overlay region, meaning the same geographic area is served by multiple area codes. Overlay codes were introduced to meet growing demand for phone numbers without requiring existing customers to change their numbers.

This area code shares its geographic region with: area code 713 (Houston).

In service since: 23-Jan-2025

Learn more about overlay and split area codes →

Demographics & Economics

Demographic Data Unavailable for Area Code 621

County-level demographic data is not available for this area code because NPA boundary polygons are not publicly distributed by NANPA. We use geographic boundary data from the Colorado Open Data Portal to map area codes to counties, which currently covers 194 of 376 geographic area codes.

Demographic statistics (population, income, education, poverty) require county-level aggregations from Census ACS data. Without a county mapping, these aggregations cannot be computed. We are actively seeking additional data sources to improve coverage.

Statistics are population-weighted aggregations from Census ACS 5-year estimates where county boundary data is available.See Sources for details.

Time Zone

  • Central Time (CT)

NANPA Relief Status

According to the latest NANPA analysis (July 2026), this area code is not currently listed as exhausting within the next 36 months. No relief planning is in progress for this NPA.

Source: NANPA NPA Relief Planning Reports · See all relief planning statuses

Current Time

Central Time (CT)
 
 

Prefix Utilization

Geographic Coverage

State

TX

Major Cities

  • Houston
  • Pasadena
  • Pearland
  • The Woodlands
  • Sugar Land
  • Atascocita
  • Baytown
  • Spring
  • Channelview
  • Friendswood
  • Rosenberg
  • Mission Bend
  • La Porte
  • Deer Park
  • Alvin
  • Fulshear
  • Sienna
  • Pecan Grove
  • Cloverleaf
  • Fresno
  • Katy
  • Dickinson
  • Cinco Ranch
  • Stafford

and 74 more cities

Area Code 621 geographic coverage map (light mode)

Demographics

Detailed demographic and economic data is not yet available for area code 621.

History

Area code 621 serves as an overlay for the same territory as area code 713. It was introduced in 2025 to provide additional phone number capacity for the region. It shares its territory with area codes area code 281 and area code 346 and area code 713 and area code 832.

County Coverage

Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 621).

CountyPopulationShare
Harris, TX5,201,14664.2%
Fort Bend, TX1,310,16516.2%
Montgomery, TX473,2825.8%
Brazoria, TX349,2774.3%
Galveston, TX267,6193.3%
Waller, TX248,1513.1%
Chambers, TX130,0551.6%
Liberty, TX104,2481.3%
San Jacinto, TX17,8160.2%
Polk, TX2400.0%

Area Code 621 Family Tree

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713281409832936979346621
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Area code 621 was originally assigned in 23-Jan-2025 to serve TX.

Call Context

Regional geographic area

This area code covers a geographic region across TX, including Houston and surrounding communities.

Nearby Area Codes

Area codes geographically closest to 621.

Area code 979 map card showing College Station (light mode)
979TXCollege StationCentral Time (CT)Split
Area code 409 map card showing Beaumont (light mode)
409TXBeaumontCentral Time (CT)Split
Area code 936 map card showing The Woodlands (light mode)
936TXThe WoodlandsCentral Time (CT)Split
Area code 512 map card showing Austin (light mode)
512TXAustinCentral Time (CT)Geographic

Other Area Codes in Texas

Area codes that also serve Texas, linked for easy comparison.