- Lead
- 3,348
- Total
- 52,878
- vs nation
- D+7.8
Illinois 66th State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 5,896
- Total
- 54,669
- vs nation
- D+6.3
- Lead
- 2,890
- Total
- 47,691
- vs nation
- D+4.0
- Lead
- 49
- Total
- 43,971
- vs nation
- R+3.7
- Lead
- 5,758
- Total
- 46,715
- vs nation
- D+5.1
- Lead
- 4,817
- Total
- 40,972
- vs nation
- R+9.3
- Lead
- 4,170
- Total
- 34,102
- vs nation
- R+12.7
- Lead
- 1,430
- Total
- 27,357
- vs nation
- R+13.7
Key facts
- 2024 presidential margin
- D+6.3MIT Election Lab
- Population
- 108,6502024 5-year
- Population density
- 1,986 / sq mi2024 5-year · TIGER/Line
- Land area
- 54.7 sq miTIGER/Line
- Median household income
- $109,7752024 5-year
- White (non-Hispanic)
- 66.3%2024 5-year
- Black
- 3.2%2024 5-year
- Hispanic / Latino
- 19.8%2024 5-year
- Peak Democratic margin
- D+12.3 in 2008MIT Election Lab
- Peak Republican margin
- R+67.3 in 1920MIT Election Lab
- Most similar
- State House District 83, IL · twin score 92.7
presidential history
Party record book
Illinois 66th 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
55.2%
25,806 votes · D+12.3 · modeled estimate
Runner-up · Joe Biden, 2020 · 54.3%
Republican
Warren G. Harding1920
81.7%
5,106 votes · R+67.3 · modeled estimate
Runner-up · Dwight D. Eisenhower, 1956 · 73.9%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
29,668votes
54.3% of the vote · D+10.8 · modeled estimate
Runner-up · Kamala Harris, 2024 · 27,510 votes
Republican
Donald Trump2024
24,162votes
45.7% of the vote · D+6.3 · modeled estimate
Runner-up · Donald Trump, 2020 · 23,772 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
Kamala Harris2024
+7.8pts D vs U.S.
Place D+6.3 · U.S. R+1.5 · modeled estimate
Runner-up · Joe Biden, 2020 · +6.3 pts
Republican
Charles E. Hughes1916
+42.0pts R vs U.S.
Place R+38.9 · U.S. D+3.1 · modeled estimate
Runner-up · Warren G. Harding, 1920 · +41.1 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.
| Year | Vote lead | Democratic | Republican | Total |
|---|---|---|---|---|
| 2024 | D | 51.1%25,425 | 48.9%24,329 | 49,754 |
| 2020 | D | 54.2%27,091 | 45.8%22,911 | 50,002 |
The district recorded a Democratic presidential margin of D+6.4 in 2024 and D+12.3 in 2008, switching sides at least once in between. About 48,100 residents lived here, with White alone at 61.7% in the 2024 ACS 5-year.
Across the recorded series it reached a Democratic high of 12.3 points in 2008 and a Republican high of 67.3 points in 1920. Between 2020 and 2024 the district moved 4.5 points toward the Republican candidate; the 2024 margin was 6.3 points.
A population of 108,650, a 66% non-Hispanic-white share, and a median household income of $109,775 describe the district. The district's voting pattern over the last decade is most similar to that of State House District 83 and State House District 63.
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 66th State House District. Akashic. https://akashic.app/sld-lower/17066/. Accessed May 20, 2026. License: CC BY 4.0.