Cost of living in O'Fallon, MO

O'Fallon is a Census city in St. Charles County, MO. ACS 2024 5-year population is 93,801. Median gross rent is $1,443 (ACS 2024 5-year, this place). Median home value is $326,200. Median household income is $110,443. Insurance is the NAIC state average; food is a USDA plan — no town indexes.