O'Fallon Population 2026
O'Fallon has a population of 29,002, making it the #1609 biggest city in 🇺🇸 United States, located in Illinois. It is about 304× smaller than New York City, the country's biggest city.
Population (city proper)
29,002
Rank in United States
#1609
Coordinates
38.59°N, 89.91°W
~167 m elevation · America/Chicago
Distance to capital (Washington)
1,116 km
693 miles, straight line
Other big cities in Illinois
| City | Population | Rank in United States |
|---|---|---|
| Chicago | 2,664,452 | #3 |
| Aurora | 200,661 | #125 |
| Rockford | 148,278 | #184 |
| Joliet | 147,861 | #186 |
| Naperville | 147,100 | #190 |
| Peoria | 115,070 | #259 |
| Springfield | 114,394 | #262 |
| North Peoria | 113,004 | #266 |
Cities near O'Fallon
- Fairview Heights16,827 people · ~7 km away
- Belleville42,034 people · ~10 km away
- Collinsville24,754 people · ~11 km away
- East Saint Louis27,006 people · ~21 km away
- Granite City29,054 people · ~24 km away
- Edwardsville24,992 people · ~25 km away
FAQ
What is the population of O'Fallon?
O'Fallon has a population of 29,002 (city proper, latest official figure via GeoNames), making it the #1609 biggest city in United States.
What state is O'Fallon in?
O'Fallon is located in Illinois, United States.
Is O'Fallon the capital of United States?
No, the capital of United States is Washington D.C., about 1,116 km away.
Sources & notes
Population refers to the city proper (municipal boundaries), not the metropolitan area. Source: GeoNames (CC BY 4.0), retrieved 2026-07-07. Country data: UN World Population Prospects 2024.
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