Cost of living in O'Fallon, IL

O'Fallon is a Census city in St. Clair County, IL. ACS 2024 5-year population is 32,262. Median gross rent is $1,332 (ACS 2024 5-year, this place). Median home value is $295,700. Median household income is $105,982. Insurance is the NAIC state average; food is a USDA plan — no town indexes.