Texas State Senate District 21

State Legislative District Profile (Upper Chamber)

Overview

District ID
tx-sd-021
State
Texas
Chamber
Upper chamber (state senate)
District Code
021
Land Area
16,508.6 sq mi
Water Area
175.8 sq mi

Boundary

Boundary of Texas State Senate District 21

Boundary as GeoJSON

Source: U.S. Census Bureau TIGER/Line state legislative district boundaries.

Counties

CountyOverlapShare of district landShare of county land
Webb County3361.48 sq mi20.4%100.0%
Duval County1793.48 sq mi10.9%100.0%
La Salle County1486.70 sq mi9.0%100.0%
Dimmit County1328.88 sq mi8.0%100.0%
Starr County1223.18 sq mi7.4%100.0%
McMullen County1139.80 sq mi6.9%100.0%
Jim Hogg County1136.17 sq mi6.9%100.0%
Live Oak County1039.69 sq mi6.3%100.0%
Zapata County998.41 sq mi6.0%100.0%
Wilson County803.73 sq mi4.9%100.0%
Karnes County747.75 sq mi4.5%100.0%
Caldwell County544.54 sq mi3.3%100.0%
Guadalupe County427.74 sq mi2.6%60.1%
Hays County207.12 sq mi1.3%30.6%
Travis County168.06 sq mi1.0%16.9%
Bexar County101.89 sq mi0.6%8.2%

Showing all 16 counties

Places

PlaceOverlapShare of district landShare of place land
Laredo city106.49 sq mi0.6%97.6%
Austin city64.69 sq mi0.4%19.8%
San Marcos city35.59 sq mi0.2%89.1%
Kyle city31.00 sq mi0.2%95.3%
Lockhart city15.61 sq mi0.1%96.2%
La Moca Ranch CDP15.05 sq mi0.1%100.0%
Garfield CDP11.98 sq mi0.1%100.0%
Rio Grande City city11.35 sq mi0.1%100.0%
Floresville city7.69 sq mi<0.1%100.0%
Zapata CDP7.64 sq mi<0.1%100.0%
Creedmoor city7.62 sq mi<0.1%100.0%
Hebbronville CDP6.48 sq mi<0.1%100.0%
Redwood CDP6.45 sq mi<0.1%100.0%
Elmendorf city6.14 sq mi<0.1%100.0%
Buda city6.10 sq mi<0.1%63.4%
Roma city5.86 sq mi<0.1%100.0%
Luling city5.51 sq mi<0.1%100.0%
San Antonio city4.98 sq mi<0.1%1.0%
Freer city4.12 sq mi<0.1%100.0%
Las Lomitas CDP3.95 sq mi<0.1%100.0%
Thompsonville CDP3.89 sq mi<0.1%100.0%
Catarina CDP3.76 sq mi<0.1%100.0%
Mustang Ridge city3.72 sq mi<0.1%99.8%
Niederwald city3.67 sq mi<0.1%100.0%
Kenedy city3.67 sq mi<0.1%83.1%

Showing top 25 of 219 places

Overlapping Congressional Districts

Congressional districtPopulation in bothShare of this district's populationShare of the congressional district's populationShare of this district's land
TX District 28380,05841.9%49.6%59.1%
TX District 35287,99031.7%37.5%1.7%
TX District 1598,73310.9%12.9%18.3%
TX District 3751,0655.6%6.7%0.1%
TX District 2745,8835.1%6.0%3.3%
TX District 2128,9343.2%3.8%0.5%
TX District 2315,2791.7%2.0%17.1%

Source: U.S. Census Bureau 2020 blocks and 2025 block equivalency files (119th Congress, 2024 state legislative plans).

Voters

Registered Voters
560,002
Active Voters
525,747 (93.9%)

Party Registration

This state's voter file does not record party registration.

Turnout by Cycle

CycleGeneralDemocratic PrimaryRepublican Primary
2023–2024311,757 (55.7%)62,319 (11.1%)38,092 (6.8%)
2021–2022219,066 (39.1%)63,384 (11.3%)32,919 (5.9%)
2019–2020278,945 (49.8%)98,174 (17.5%)28,307 (5.1%)
2017–2018196,565 (35.1%)66,943 (12.0%)18,957 (3.4%)
2015–2016194,646 (34.8%)72,116 (12.9%)33,032 (5.9%)
2013–201492,483 (16.5%)47,843 (8.5%)13,213 (2.4%)
2011–2012149,461 (26.7%)45,587 (8.1%)13,588 (2.4%)

Turnout counts today's registered voters with a counted ballot in the cycle's elections (the odd and even year), as a share of today's registered voters. Voters who have since left the rolls are not counted.

Browse the voter list for this district (premium access; sign-in required)

Source: Civitech voter file snapshot as of 08/14/2025. These are registered voters, separate from the Census population figures. Counts under 10 are suppressed and shown as "<10".

Demographics

Total Population
932,499 (± 5,551)
Median Age
32.7
Median Household Income
$69,461 (± $1,455)
High School Graduate or Higher (age 25+)
79.8%
Bachelor's Degree or Higher (age 25+)
27.6%

Population by Age

GroupPeopleShare
Under 18229,48324.6%
18 to 64598,73764.2%
65 and over104,27911.2%

Population by Race and Hispanic Origin

GroupPeopleShare
Hispanic or Latino (any race)639,22068.5%
White, not Hispanic222,77323.9%
Black, not Hispanic31,5093.4%
Asian, not Hispanic16,1021.7%
American Indian / Alaska Native, not Hispanic1,0070.1%
Native Hawaiian / Pacific Islander, not Hispanic2080.0%
Some other race, not Hispanic4,5830.5%
Two or more races, not Hispanic17,0971.8%

Source: U.S. Census Bureau, American Community Survey 2020-2024 ACS 5-year estimates (tables B01001, B01002, B01003, B03002, B15003, B19013) for this state legislative district. Estimates are survey-based; ± figures are 90% margins of error.

Citizen Voting Age Population

Total Citizen Population
821,811
Citizen Voting Age Population (CVAP)
600,091

Citizen Population by Race/Ethnicity

GroupCitizensShare
Non-Hispanic283,16434.5%
Hispanic538,64665.5%
White226,65727.6%
Black30,8563.8%
Asian11,5711.4%
American Indian / Alaska Native1,0260.1%
Native Hawaiian / Pacific Islander1820.0%
Two or More Races1,4100.2%

Citizen Voting Age Population by Race/Ethnicity

GroupCVAPShare
Non-Hispanic240,35440.1%
Hispanic359,73759.9%
White194,42032.4%
Black27,6914.6%
Asian13,1192.2%
American Indian / Alaska Native4,2610.7%
Native Hawaiian / Pacific Islander1210.0%
Two or More Races1,1490.2%

Source: Redistricting Data Hub / U.S. Census Bureau CVAP Special Tabulation (2020-2024 ACS 5-year).