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, Native Hawaiian or Pacific Islander and multiracial populations.

Population by Race

White

Black or African American

Two or more races

Asian

Other race

Native American

Native Hawaiian or Pacific Islander

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%
Native Hawaiian or Pacific Islander	0	0%

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