- Lead
- 9,578
- Total
- 36,720
- vs nation
- D+27.6
Illinois 21st State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 15,912
- Total
- 40,318
- vs nation
- D+35.0
- Lead
- 15,538
- Total
- 36,932
- vs nation
- D+40.0
- Lead
- 12,761
- Total
- 34,173
- vs nation
- D+33.5
- Lead
- 15,026
- Total
- 35,740
- vs nation
- D+34.8
- Lead
- 9,659
- Total
- 35,389
- vs nation
- D+29.8
- Lead
- 8,602
- Total
- 31,915
- vs nation
- D+26.4
- Lead
- 8,259
- Total
- 29,868
- vs nation
- D+19.1
Key facts
- 2024 presidential margin
- D+26.1MIT Election Lab
- Population
- 108,7812024 5-year
- Population density
- 5,977 / sq mi2024 5-year · TIGER/Line
- Land area
- 18.2 sq miTIGER/Line
- Median household income
- $79,6752024 5-year
- White (non-Hispanic)
- 33.9%2024 5-year
- Black
- 6.5%2024 5-year
- Hispanic / Latino
- 55.6%2024 5-year
- Peak Democratic margin
- D+42.1 in 2016MIT Election Lab
- Peak Republican margin
- R+60.5 in 1920MIT Election Lab
- Most similar
- State House District 2, IL · twin score 99.2
presidential history
Party record book
Illinois 21st State House 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
Barack Obama2008
70.8%
25,298 votes · D+42.0 · modeled estimate
Runner-up · Joe Biden, 2020 · 68.9%
Republican
Warren G. Harding1920
78.2%
13,547 votes · R+60.5 · modeled estimate
Runner-up · Theodore Roosevelt, 1904 · 67.8%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
27,763votes
68.9% of the vote · D+39.5 · modeled estimate
Runner-up · Barack Obama, 2008 · 25,298 votes
Republican
Dwight D. Eisenhower1956
27,640votes
64.4% of the vote · R+28.9 · modeled estimate
Runner-up · Richard Nixon, 1972 · 26,119 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
Hillary Clinton2016
+40.0pts D vs U.S.
Place D+42.1 · U.S. D+2.1 · modeled estimate
Runner-up · Joe Biden, 2020 · +35.0 pts
Republican
Warren G. Harding1920
+34.3pts R vs U.S.
Place R+60.5 · U.S. R+26.2 · modeled estimate
Runner-up · Theodore Roosevelt, 1904 · +25.9 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.
| Year | Vote lead | Democratic | Republican | Total |
|---|---|---|---|---|
| 2024 | D | 73.1%30,511 | 26.9%11,209 | 41,720 |
Illinois 21st State House District sits in the Upper Midwest. In 2024 it voted Democratic.
Across the recorded series it reached a Democratic high of 42.1 points in 2016 and a Republican high of 60.5 points in 1920. Between 2020 and 2024 the district moved 13.4 points toward the Republican candidate; the 2024 margin was 26.1 points.
A population of 108,781, a 34% non-Hispanic-white share, and a median household income of $79,675 describe the district. The district's voting pattern over the last decade is most similar to that of State House District 2 and State House District 43.
The state-house 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 →
Illinois 21st State House District. Akashic. https://akashic.app/sld-lower/17021/. Accessed May 20, 2026. License: CC BY 4.0.