Waterloo

County:: Monroe County
County Seat:: Yes
Area (mi²):: 8.234
State:: Illinois

Waterloo is a city located in Monroe County, Illinois. Waterloo has a 2025 population of 11,236. It is also the county seat of Monroe County. Waterloo is currently growing at a rate of 0.41% annually and its population has increased by 2.1% since the most recent census, which recorded a population of 11,005 in 2020.

The average household income in Waterloo is $109,698 with a poverty rate of 5.47%. The median age in Waterloo is 40.2 years: 38.7 years for males, and 41.9 years for females.

Demographics

The racial composition of Waterloo includes 95.86% White, and smaller percentages for Two or more races, Asian, Black or African American, other race, Native American, Native Hawaiian or Pacific Islander and multiracial populations.

Population by Race

White

Two or more races

Asian

Black or African American

Other race

Native American

Native Hawaiian or Pacific Islander

Race	Population	Percentage (of total)
White	10,597	95.86%
Two or more races	188	1.7%
Asian	123	1.11%
Black or African American	90	0.81%
Other race	41	0.37%
Native American	16	0.14%
Native Hawaiian or Pacific Islander	0	0%

Waterloo Marital Status

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

Waterloo's average per capita income is $61,456. Household income levels show a median of $92,005. The poverty rate stands at 5.47%.

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	$136,288	-
Families	$122,833	$134,067
Households	$92,005	$109,698
Non Families	$45,354	$53,649

$61,456

Average Income

$92,005

Median Household Income

5.47%

Poverty Rate