- Lead
- 16,238
- Total
- 38,990
- vs nation
- D+43.1
Illinois 31st State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 26,283
- Total
- 46,722
- vs nation
- D+51.8
- Lead
- 29,172
- Total
- 46,885
- vs nation
- D+60.1
- Lead
- 25,565
- Total
- 43,589
- vs nation
- D+54.8
- Lead
- 29,011
- Total
- 46,586
- vs nation
- D+55.0
- Lead
- 22,716
- Total
- 43,970
- vs nation
- D+54.1
- Lead
- 20,087
- Total
- 39,399
- vs nation
- D+50.5
- Lead
- 18,395
- Total
- 36,444
- vs nation
- D+42.0
Key facts
- 2024 presidential margin
- D+41.6MIT Election Lab
- Population
- 108,6382024 5-year
- Population density
- 6,790 / sq mi2024 5-year · TIGER/Line
- Land area
- 16 sq miTIGER/Line
- Median household income
- $60,4832024 5-year
- White (non-Hispanic)
- 32.3%2024 5-year
- Black
- 51.0%2024 5-year
- Hispanic / Latino
- 12.8%2024 5-year
- Peak Democratic margin
- D+62.3 in 2008MIT Election Lab
- Peak Republican margin
- R+39.9 in 1920MIT Election Lab
- Most similar
- State House District 28, IL · twin score 99.1
presidential history
Party record book
Illinois 31st 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
81.0%
37,734 votes · D+62.3 · modeled estimate
Runner-up · Hillary Clinton, 2016 · 79.5%
Republican
Warren G. Harding1920
67.4%
11,262 votes · R+39.9 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · 60.6%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Barack Obama2008
37,734votes
81.0% of the vote · D+62.3 · modeled estimate
Runner-up · Hillary Clinton, 2016 · 37,289 votes
Republican
Dwight D. Eisenhower1956
23,272votes
50.7% of the vote · R+1.4 · modeled estimate
Runner-up · Richard Nixon, 1972 · 22,189 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
+60.1pts D vs U.S.
Place D+62.2 · U.S. D+2.1 · modeled estimate
Runner-up · Barack Obama, 2008 · +55.0 pts
Republican
Warren G. Harding1920
+13.7pts R vs U.S.
Place R+39.9 · U.S. R+26.2 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · +9.3 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%30,471 | 26.9%11,194 | 41,665 |
With a 2024 presidential margin of D+41.5, this district ranks among the state's most reliably left-leaning constituencies, suggesting a dense urban core and a voter base that has shifted sharply in one partisan direction over recent cycles.
Across the recorded series it reached a Democratic high of 62.3 points in 2008 and a Republican high of 39.9 points in 1920. Between 2020 and 2024 the district moved 14.6 points toward the Republican candidate; the 2024 margin was 41.6 points.
A population of 108,638, a 32% non-Hispanic-white share, and a median household income of $60,483 describe the district. The district's voting pattern over the last decade is most similar to that of State House District 28 and State House District 27.
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.
Compare State House District 31 with…
- Los Angeles County, CAThe two largest Democratic-anchor counties in America.
- New York County, NYCook vs Manhattan — Midwest blue vs East-coast bluest.
- Harris County, TXCook vs Harris — Midwest blue vs Sun Belt swing.
Open campaign intelligence report → · All twelve comparisons →
Illinois 31st State House District. Akashic. https://akashic.app/sld-lower/17031/. Accessed May 20, 2026. License: CC BY 4.0.