O'Fallon is a city in St. Clair County, Illinois, United States. The 2020 census listed the population at 32,289. The city is the second largest city in the Metro East region and Southern Illinois. It sits 5 miles (8.0 km) from Scott Air Force Base and 18 miles (29 km) from Downtown St. Louis. Like its namesake in St. Charles County, Missouri, O'Fallon is part of the St. Louis metro area. This makes O'Fallon (along with the two Troys in Illinois and Missouri) one of the few pairs of like-named municipalities to be part of the same metro region.

Official town website ↗

From Wikipedia, licensed CC BY-SA 4.0 · facts via Wikidata (CC0)

How O'Fallon ranks

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#26Fewest uninsured in IL #36Fastest growing in IL #38Closest to a top hospital in IL All IL rankings →

Town numbers

ZIP code62269

Area code618

Living in O'Fallon

Housing in O'Fallon

$300K Median sale price · Redfin, May 2026

The median sale price was $300,000 in May 2026.

A strong seller's market

Buyer’sBalancedSeller’s

Days on market37

Sale-to-list99.5%

Sold in May57

Zillow Home Value Index · Redfin Data CenterHousing market →

Safety in O'Fallon

Safety Grade B

O'Fallon reports less crime per resident than 55% of the U.S. towns and cities we grade.

Violent crime per 1,000

O'Fallon 1.4

Illinois 2.6

U.S. 3.3

Property crime per 1,000

O'Fallon 9.1

Illinois 15.6

U.S. 15.5

FBI crime data, 2025 · crimes reported to policeCrime & safety →

Work & commute in O'Fallon

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Most working residents leave O'Fallon for work: only 13% work in town. The top destinations are St. Louis (12%), Belleville (9%) and Fairview Heights (4%). Half commute less than 15 miles.

St. Louis, MO

12%

Belleville

Fairview Heights

Edwardsville

13%Work in townlive and work in O'Fallon 15 miWhere do people commute?the commute map 11,482Jobs based herebalanced

Census LEHD 2023 · ACSWork & commute in O'Fallon →

Health in O'Fallon

Health Grade A

Healthier than 88% of U.S. towns on seven CDC estimates.

Compared with Illinois

14better than IL

of 32 measures CDC estimates. The other 18 are too close to call.

Conditions 4▲ 8 close Habits 1▲ 3 close Care 3▲ 4 close Mind 2▲ 3 close Everyday needs 4▲ 0 close

BetterToo close to callWorse

What stands out

5.4%Fewer uninsured adultsIL 9.9% · better 10.1%Fewer adults facing food insecurityIL 15.9% · better

Care nearby

Hshs St. Elizabeth's HospitalO Fallon · 1.5 mi · ER

Sihf Healthcare - O'fallonO Fallon · 1.4 mi · sliding-scale fees

Primary careShortage · county-wide

DentalShortage · county-wide

Mental healthShortage · county-wide

CDC PLACES 2025 · modeled estimates for adults · CDC's estimate for O'Fallon · CMS · HRSAHealth in O'Fallon →

Natural hazards in O'Fallon

Moderate

Expected storm and flood damage is higher than in 57% of U.S. communities.

🌊 Inland flooding🏚️ Earthquakes🌡️ Heat waves

12Does O'Fallon flood?paid flood claims since 2000 3Disasters that paid out herefederal disasters sent FEMA money to O'Fallon MapO'Fallon vs. its neighborsnearby towns shaded by rating

FEMA National Risk Index December 2025 · OpenFEMANatural hazards in O'Fallon →

Climate in O'Fallon

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O'Fallon has chilly winters and warm summers. A typical July afternoon reaches 88°, a January night drops to 23°, and about 11 inches of snow falls in a normal winter.

43° / 26°Winter

66° / 45°Spring

87° / 66°Summer

68° / 47°Fall