Waterloo, Illinois Demographics & Population 2026
During the 2020–2024 ACS period, Waterloo, Illinois had a total population of 11,129, the 208th largest city in Illinois, with a median household income of $98,711, which is 18% higher than the state average. The poverty rate is 5.9%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
Key Takeaways
- Near full employment with an unemployment rate of just 2.3%.
Waterloo Quick Facts
How Waterloo Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 11,055 | 11,129 | +0.7% |
| Median household income | $92,005 | $98,711 | +7.3% |
| Median home value | $237,900 | $249,500 | +4.9% |
How Waterloo Compares
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
A less diverse community where one racial or ethnic group represents a large majority.
State average: 61 | National average: 61
Education
Educational Attainment (Adults 25+)
Waterloo Rankings in Illinois
Explore Illinois Rankings
Other Cities in Monroe County
Cities Similar to Waterloo
These cities in the same state have comparable population and economic profiles.
| City | Population | Median Income | Home Value | Bachelor's+ | Poverty |
|---|---|---|---|---|---|
| Columbia | 11,127 | $107,606 | $293,000 | 49.0% | 5.4% |
| Gages Lake | 10,819 | $103,318 | $310,500 | 42.5% | 7.0% |
| Roscoe | 10,706 | $93,036 | $227,800 | 32.5% | 5.5% |
| Pingree Grove | 10,914 | $114,294 | $320,800 | 42.9% | 1.2% |
| Troy | 11,647 | $112,434 | $268,000 | 45.2% | 2.0% |
Population Overview
Waterloo is a small city located in Illinois, within Monroe County. The total population is 11,129. It ranks as the 208th most populous out of 1,445 Census-designated places in Illinois.
Age Demographics
The median age in Waterloo is 41.5 years. This is 6% higher than the state median of 39.0 years.
Economy, Income & Housing
The median household income in Waterloo is $98,711. This is 18% higher than the state median of $83,390. It is also 22% higher than the national median of $80,734. The poverty rate stands at 5.9%. This is 50% lower than the state poverty rate of 11.8%. The unemployment rate is 2.3%. This is 61% lower than the state rate of 5.8%. The median home value is $249,500. Housing costs are 5% lower than the state median of $263,300. With a home-value-to-income ratio of just 2.5x, Waterloo is one of the most affordable housing markets in the area. 78.2% of occupied housing units are owner-occupied. This homeownership rate is 17% higher than the state average of 67.1%.
Race & Ethnicity
Waterloo has a predominantly White (non-Hispanic) population, comprising 94.1% of all residents. Hispanic or Latino residents account for 1.8%. The White (non-Hispanic) population is significantly higher than the state average (94.1% vs 58.1%). The Black or African American population (1.0%) is well below the state average of 13.3%. The Hispanic or Latino population (1.8%) is well below the state average of 18.8%. The Asian population (1.7%) is well below the state average of 5.9%.
Education
37.3% of residents aged 25 and older hold a bachelor's degree or higher. This is 1% lower than the state rate of 37.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 96.7%.
Data Sources & Methodology
All demographic data for Waterloo, Illinois is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against Illinois state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 1,445 Census-designated places in Illinois. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.
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Frequently Asked Questions
What is the population of Waterloo, Illinois?
Waterloo, Illinois has a population of 11,129 according to the most recent U.S. Census ACS 5-Year Estimates.
What is the median household income in Waterloo, IL?
The median household income in Waterloo is $98,711, which is 22% higher than the national median of $80,734.
What is the poverty rate in Waterloo, IL?
The poverty rate in Waterloo is 5.9%. This means approximately 641 residents live below the federal poverty line.
What is the racial makeup of Waterloo, Illinois?
Waterloo's population is 94.1% White, 1.0% Black, 1.8% Hispanic/Latino, and 1.7% Asian.
What is the median home value in Waterloo, IL?
The median home value in Waterloo is $249,500. The home-value-to-income ratio is 2.5x.
How educated is Waterloo, Illinois?
37.3% of adults (25+) in Waterloo hold a bachelor's degree or higher, and 13.8% hold a graduate or professional degree.