- Lead
- 90,384
- Total
- 414,411
- vs nation
- R+20.3
Texas 21st Congressional District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 66,171
- Total
- 395,554
- vs nation
- R+21.2
- Lead
- 74,141
- Total
- 305,770
- vs nation
- R+26.3
- Lead
- 86,234
- Total
- 269,584
- vs nation
- R+35.8
- Lead
- 70,854
- Total
- 268,570
- vs nation
- R+33.7
- Lead
- 94,085
- Total
- 244,591
- vs nation
- R+36.0
- Lead
- 77,771
- Total
- 202,926
- vs nation
- R+38.8
- Lead
- 39,030
- Total
- 168,585
- vs nation
- R+31.7
Key facts
- 2024 presidential margin
- R+21.8MIT Election Lab
- Population
- 766,9242024 5-year
- Population density
- 124 / sq mi2024 5-year · TIGER/Line
- Land area
- 6,194 sq miTIGER/Line
- Median household income
- $87,5942024 5-year
- White (non-Hispanic)
- 54.3%2024 5-year
- Black
- 3.7%2024 5-year
- Hispanic / Latino
- 34.6%2024 5-year
- Peak Democratic margin
- D+58.1 in 1932MIT Election Lab
- Peak Republican margin
- R+43.3 in 1984MIT Election Lab
- Most similar
- Congressional District 31, TX · twin score 85.4
presidential history
Party record book
Texas 21st Congressional District · the strongest Democratic and Republican presidential performances recorded here, measured three ways.
1892–2024 (partial returns from 1876) · 38 presidential cycles · 38 with a vote-share denominator · 34 with a national benchmark
Highest vote share
Largest share of the presidential candidate vote cast here.
Democratic
Franklin D. Roosevelt1932
78.6%
19,003 votes · D+58.1 · modeled estimate
Runner-up · Franklin D. Roosevelt, 1936 · 62.9%
Republican
Ronald Reagan1984
71.5%
104,737 votes · R+43.3 · modeled estimate
Runner-up · Richard Nixon, 1972 · 70.9%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
161,546votes
40.8% of the vote · R+16.7 · modeled estimate
Runner-up · Kamala Harris, 2024 · 159,567 votes
Republican
Donald Trump2024
249,951votes
60.3% of the vote · R+21.8 · modeled estimate
Runner-up · Donald Trump, 2020 · 227,717 votes
Best relative to the U.S.
This Place’s margin against the national margin in the same election — positive when it leaned toward the party more than the country did.
Democratic
Franklin D. Roosevelt1932
+40.3pts D vs U.S.
Place D+58.1 · U.S. D+17.8 · modeled estimate
Runner-up · Alton B. Parker, 1904 · +37.3 pts
Republican
George W. Bush2000
+38.8pts R vs U.S.
Place R+38.3 · U.S. D+0.5 · modeled estimate
Runner-up · George W. Bush, 2004 · +36.0 pts
Current officeholders
Federal officeholders only. State and local officeholders are planned for the next data pass.
Senate and governor results are in the Office selector at the top of this page.
U.S. House
Each result reflects the U.S. House district as it was drawn for that election; redistricting has redrawn these lines over time, so they can differ from the current 120th-Congress district shown on the map above.
Stretching from San Antonio's northern suburbs through the Texas Hill Country to the Permian Basin fringe, TX-21 has trended closer in presidential cycles as Bexar and Travis County spillover precincts add college-educated voters to an otherwise rural base.
Across the recorded series it reached a Democratic high of 58.1 points in 1932 and a Republican high of 43.3 points in 1984. Between 2020 and 2024 the district moved 5.1 points toward the Republican candidate; the 2024 margin was 21.8 points.
A population of 766,924, a 54% non-Hispanic-white share, and a median household income of $87,594 describe the district. The district's voting pattern over the last decade is most similar to that of Congressional District 31 and Congressional District 11.
The congressional districts whose fingerprint — 2000–2024 trajectory, demographics, ancestry, religion — sits closest to this one, and why.
Twin score (0–100) = weighted cosine between tier-standardized fingerprints: presidential margins 2000–2024 with 12-yr trend and elasticity, ACS income, age, education, population and race, top reported ancestries, and religious adherence — chips name the closest-shared dimensions and the widest gap. Re-weight the groups in the twins explorer.
District research tools
Open the source-auditable district brief for electoral baseline, electorate, current-cycle coverage, geography, official dates, and methodology. Open campaign intelligence report → · Browse all comparisons →
Texas 21st Congressional District. Akashic. https://akashic.app/cd/4821/. Accessed May 20, 2026. License: CC BY 4.0.