Waterloo Flag

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 11,165 . It is also the county seat of Monroe County . Waterloo is currently declining at a rate of -0.33% annually but its population has increased by 1.46% since the most recent census, which recorded a population of 11,004 in 2020.

The median household income in Waterloo is $92,005 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. For every 100 females there are 97.0 males.

11.2K
Total Population
1,356
Density (mi²)
-37 -0.33%
Growth

Waterloo Population

Waterloo Population

Data after 2023 is projected based on recent change

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 and multiracial populations.

Population by Race

White (95.86%)

Two or more races (1.7%)

Asian (1.11%)

Black or African American (0.81%)

Other race (0.37%)

Native American (0.14%)

Race
Population
Percentage (of total)
White10,59795.86%
Two or more races1881.7%
Asian1231.11%
Black or African American900.81%
Other race410.37%
Native American160.14%

Waterloo Marital Status

OverallMalesFemales0%10%20%30%40%50%60%70%80%90%100%

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

Nearby Cities

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)