Waterloo city, Illinois
Official LSAD Designation: Waterloo city • Census GEOID: 1779150
• Monroe County
Waterloo city is an incorporated city in Monroe County, Illinois. According to official records from the Census (2025), Waterloo city had an estimated population of 11,132 residents. Official Census Bureau geographic records classify this community under LSAD designation Waterloo city (GEOID 1779150).
Local Government Administration U.S. Census Bureau GMAF
City Of Waterloo
Municipal
Official Title:
Collector-budget Officer
Address:
100 W 4TH ST, WATERLOO IL 62298-1333
County Of Monroe
County
Official Title:
Treasurer
Address:
100 S MAIN ST, WATERLOO IL 62298
Civic & Statistical Snapshot
| Category | Estimate | Survey Period / Source |
|---|---|---|
| Total Population | 11,132 | 2025 |
| Median Household Income | $98,711 | 2020-2024 |
| Median Home Value | $249,500 | 2020-2024 |
| Land Area | 8.29 sq mi | Gazetteer (2026) |
| Civic & Public Services | Hospitals, Libraries, Colleges | CMS / IMLS / IPEDS |
| Schools & Districts | NCES Directory Listings | Provided by k12guides.com |
| Nearby Airports | Landing Facilities | Provided by airport-data.com |
| Climate & Weather | NOAA 30-Year Normals | 1991–2020 |
Source: U.S. Census Bureau (PEP, ACS 5-Year).