- Lead
- 34,384
- Total
- 95,829
- vs nation
- R+34.4
Missouri 21st State Senate District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 33,041
- Total
- 95,177
- vs nation
- R+39.2
- Lead
- 29,377
- Total
- 86,467
- vs nation
- R+36.1
- Lead
- 19,268
- Total
- 83,166
- vs nation
- R+27.0
- Lead
- 11,862
- Total
- 86,855
- vs nation
- R+20.9
- Lead
- 15,725
- Total
- 81,704
- vs nation
- R+16.8
- Lead
- 7,151
- Total
- 71,490
- vs nation
- R+10.5
- Lead
- 2,617
- Total
- 64,265
- vs nation
- R+4.4
Key facts
- 2024 presidential margin
- R+35.9MIT Election Lab
- Population
- 184,0622024 5-year
- Population density
- 56 / sq mi2024 5-year · TIGER/Line
- Land area
- 3,266 sq miTIGER/Line
- Median household income
- $80,8972024 5-year
- White (non-Hispanic)
- 86.0%2024 5-year
- Black
- 2.8%2024 5-year
- Hispanic / Latino
- 4.5%2024 5-year
- Peak Democratic margin
- D+34.5 in 1932MIT Election Lab
- Peak Republican margin
- R+36.8 in 1972MIT Election Lab
- Most similar
- State Senate District 47, IN · twin score 94.3
presidential history
Party record book
Missouri 21st State Senate 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
67.0%
35,798 votes · D+34.5 · modeled estimate
Runner-up · Samuel J. Tilden, 1876 · 64.8%
Republican
Richard Nixon1972
68.4%
40,557 votes · R+36.8 · modeled estimate
Runner-up · Donald Trump, 2024 · 67.3%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Barack Obama2008
36,801votes
42.4% of the vote · R+13.7 · modeled estimate
Runner-up · Franklin D. Roosevelt, 1932 · 35,798 votes
Republican
Donald Trump2024
64,475votes
67.3% of the vote · R+35.9 · modeled estimate
Runner-up · Donald Trump, 2020 · 63,209 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
John W. Davis1924
+36.6pts D vs U.S.
Place D+11.4 · U.S. R+25.2 · modeled estimate
Runner-up · James M. Cox, 1920 · +33.0 pts
Republican
Donald Trump2020
+39.2pts R vs U.S.
Place R+34.7 · U.S. D+4.5 · modeled estimate
Runner-up · Donald Trump, 2016 · +36.1 pts
Current officeholders
State legislative officeholder from OpenStates nightly current-legislator data.
Senate and governor results are in the Office selector at the top of this page.
U.S. House
Each row is a county-allocated estimate of U.S. House votes for this district — county returns apportioned onto its boundary, not precinct-counted. “Vote lead” is the estimated local lead here, not necessarily the winner of the full contest.
Missouri 21st State Senate District sits in the Border South. In 2024 it voted Republican.
Across the recorded series it reached a Democratic high of 34.5 points in 1932 and a Republican high of 36.8 points in 1972. Between 2020 and 2024 the district moved 1.2 points toward the Republican candidate; the 2024 margin was 35.9 points.
A population of 184,062, a 86% non-Hispanic-white share, and a median household income of $80,897 describe the district. The district's voting pattern over the last decade is most similar to that of State Senate District 47 and State Senate District 44.
The state-senate 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 →
Missouri 21st State Senate District. Akashic. https://akashic.app/sld-upper/29021/. Accessed May 20, 2026. License: CC BY 4.0.