O'Fallon

County:: St. Clair County
County Seat:: No
Area (mi²):: 15.791
State:: Illinois

O'Fallon is a city located in St. Clair County, Illinois. O'Fallon has a 2025 population of 31,742. O'Fallon is currently declining at a rate of -0.35% annually and its population has decreased by -1.75% since the most recent census, which recorded a population of 32,307 in 2020.

The average household income in O'Fallon is $131,945 with a poverty rate of 4.39%.The median age in O'Fallon is 36.9 years: 35.1 years for males, and 38.2 years for females.

Demographics

The racial composition of O'Fallon includes 72.62% White, 13.61% Black or African American, and smaller percentages for Asian, other race, Native American and multiracial populations.

Population by Race

Race	Population	Percentage (of total)
White	23,340	72.62%
Black or African American	4,375	13.61%
Two or more races	2,990	9.3%
Asian	928	2.89%
Other race	483	1.5%
Native American	23	0.07%

O'Fallon Marital Status

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

O'Fallon's average per capita income is $64,936. Household income levels show a median of $102,793. The poverty rate stands at 4.39%.

Families: A family includes the owner or renter of the home along with everyone related to them - whether through birth, marriage, or adoption. This includes relatives like spouses, children, parents, siblings, grandparents, and any other family members.

Households: A household includes all the people who occupy a housing unit (such as a house or apartment) as their usual place of residence.

Non Families: A nonfamily household is either someone living alone or when the owner/renter lives with people they aren't related to, like roommates.

Name	Median	Mean
Married Families	$146,065	-
Families	$126,776	$155,518
Households	$102,793	$131,945
Non Families	$50,481	$62,451

$64,936

Average Income

$102,793

Median Household Income

4.39%

Poverty Rate