2024 presidential election
O'Fallon
HarrisD+5.9
Constituent county margins for O'Fallon, ILOne cell per constituent county, colored by 2024 presidential margin from deep red (Republican) through neutral to deep blue (Democratic), ordered bluest first.
How it voted
Share of the 2024 vote
| Kamala Harris ✓Democratic | 51.5% | 9,086 |
|---|---|---|
| Donald TrumpRepublican | 45.6% | 8,040 |
| OtherAll other candidates | 2.9% | 516 |
D+60R+60
1 counties, each filled by 2024 D-vs-R margin.
presidential history
Presidential margin, 2008–2024
Democratic minus Republican, by election
| Year | Margin (D minus R) |
|---|---|
| 2008 | −6.9% |
| 2012 | −14.9% |
| 2016 | −10.6% |
| 2020 | +1.0% |
| 2024 | +5.9% |
DemocraticRepublican
5 presidential elections
| Year | Won | Democratic | Republican | Other | Margin | Total |
|---|---|---|---|---|---|---|
| D | 51.5%Harris9,086 | 45.6%Trump8,040 | 2.9% | 17,642 | ||
| D | 49.2%Biden8,653 | 48.2%Trump8,479 | 2.6%incl. Jorgensen | 17,593 | ||
| R | 40.8%Clinton6,278 | 51.4%Trump7,908 | 7.8%incl. Johnson | 15,378 | ||
| R | 42.5%Obama5,761 | 57.5%Romney7,786 | 0.0% | 13,547 | ||
| R | 45.8%Obama6,519 | 52.7%McCain7,505 | 1.4% | 14,230 |
Demographics
Demographic profile
Demographic Profile
Key indicators compared across containing geographies
| Indicator | O'FallonCity | IllinoisState | United StatesNation |
|---|---|---|---|
| Race & Ethnicity | |||
| White | 70.1% | 61.0% | 61.0% |
| Black | 16.9% | 13.6% | 12.2% |
| Asian | 2.6% | 6.0% | 6.0% |
| Two or more races | 8.6% | 10.9% | 12.6% |
| Other race | 1.7% | 8.6% | 8.2% |
| Hispanic or Latino | 5.1% | 18.8% | 19.3% |
| Income & Age | |||
| Median household income | $105,982 | $83,390 | $84,427 |
| Poverty rate | 6.2% | 11.8% | 12.5% |
| Median age | 37.8 | 39.1 | 39.1 |
| Age 18–24 | 8.1% | 9.1% | 9.2% |
| Age 65 and older | 17.4% | 16.9% | 17.2% |
| Education & Language | |||
| Bachelor's degree or higher (25+) | 31.8% | 37.9% | 35.6% |
| Speaks a non-English language at home | 5.0% | 24.1% | 22.3% |
| Spanish | 2.8% | 14.0% | 13.6% |
| Ancestry | |||
| Largest ancestry | German 21.5% | German 16.1% | German 12.5% |
| 2nd-largest ancestry | Irish 9.7% | Irish 10.6% | English 9.5% |
| 3rd-largest ancestry | English 8.7% | English 6.9% | Irish 9.4% |
| Religion | |||
| Catholic | 13.4%County context | 24.2% | 18.6% |
| Evangelical Protestant | 18.5%County context | 11.7% | 16.5% |
| Unaffiliated or unclaimed | 53.6%County context | 49.2% | 51.5% |
| Mainline Protestant | 5.6%County context | 5.3% | 5.2% |
| Black Protestant | 5.4%County context | 3.0% | 2.2% |
ACS values are survey estimates and may include margins of error.
Religion data may be available only at county or larger geographies. Sub-county values are labeled when inherited, modeled, or contextual.
2024 ACS
Race, ethnicity, and ancestry
Click any group to see the ancestries typically reported within it.
German
21.5%
Irish
9.7%
English
8.7%
American
4.2%
Italian
2.8%
Polish
2.6%
French
2.6%
Source · American Community Survey 5-year estimates, 2024 release. Hispanic/Latino is an ethnicity that overlaps the race categories, so these shares can total more than 100%. Ancestry is a self-reported, multiple-response item; ancestry percentages do not sum to the parent race percentage.
2024 ACS
Age distribution by sex
Median age: 37.8 in this county, 39.1 nationally
Male
Age
Female
85+
75–84
65–74
55–64
45–54
35–44
25–34
18–24
5–17
<5
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Median household income
Inflation-adjusted dollars
$105,982
O'Fallon$105,982
Illinois$83,390
United States$80,734
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Poverty rate
All persons below federal poverty line
6.2%
Children face moderate poverty.
Children under 1818.9%
Working age (18–64)11.9%
Seniors (65+)12.8%
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Language at home
Population aged 5 and older
95.0%
speak English only
Spanish2.8%
Other Indo-European0.5%
German or other West Germanic0.3%
Tagalog (incl. Filipino)0.3%
Korean0.2%
Chinese (incl. Mandarin & Cantonese)0.2%
Other Asian & Pacific Island0.2%
Arabic0.2%
French (incl. Cajun & Haitian)0.1%
Russian, Polish, or other Slavic0.1%
Vietnamese0.1%
Other languages0.1%
Source · ACS 5-year estimates, 2024.
2020 religion census
Religious adherents
Adherents per capita by tradition
Unaffiliated or not counted53.6%
Source · 2020 US Religion Census. The unaffiliated-or-not-counted share is everyone not claimed as an adherent by any reporting body — uncounted congregations as well as the religiously unaffiliated.
O'Fallon sits in the Upper Midwest. In 2024 it voted Democratic.
Across the recorded series it reached a Democratic high of 5.9 points in 2024 and a Republican high of 14.9 points in 2012. Between 2020 and 2024 the city moved 4.9 points toward the Democratic candidate; the 2024 margin was 5.9 points.
A population of 32,262, a 70% non-Hispanic-white share, and a median household income of $105,982 describe the city.
Compare two places, side by side
Twelve curated comparisons line up election history, demographics, and the divergence story for two places at a glance. Browse all comparisons →
Cite this page
All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
O'Fallon, Illinois. Akashic. https://akashic.app/city/1755249/. Accessed May 20, 2026. License: CC BY 4.0.
License: CC BY 4.0
Frequently asked questions
How did O'Fallon, Illinois vote in 2024?
In 2024, O'Fallon, Illinois voted Democratic by 5.9 points (D+5.9), carried by the Democratic candidate. Out of 17,642 votes cast, 9,086 went Democratic and 8,040 went Republican.
What is O'Fallon, Illinois's political typology?
Akashic places O'Fallon, Illinois in the "" typology. The typology is a data-driven cluster built from vote share, vote swing, race and ethnicity, income, language spoken at home, religion, and ancestry. Across 5 elections in the dataset, the city has voted Democratic 2 times, Republican 3 times, and other 0 times.
When did O'Fallon, Illinois last vote Republican?
The most recent presidential election in which O'Fallon, Illinois voted Republican was 2016.
How many people live in O'Fallon, Illinois?
O'Fallon, Illinois has a population of 32,262 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in O'Fallon, Illinois?
Median household income in O'Fallon, Illinois is $105,982 — above the national median of $80,734. The Illinois state median is $83,390.
What is the political history of O'Fallon, Illinois?
Akashic tracks 5 presidential elections in O'Fallon, Illinois from 2008 to 2024. Of those, 2 went Democratic and 3 went Republican. The city's typology — "" — captures where that record, its demographics, and its recent swing place it among American communities.