O'Fallon, Missouri

O'Fallon, Missouri
Motto: 
Tradition with Vision
Location in the state of Missouri
Coordinates: 38°47′04″N 90°43′12″W / 38.78444°N 90.72000°W / 38.78444; -90.72000
CountryUnited States
State Missouri
CountySt. Charles
MetroGreater St. Louis
First Settled1856
IncorporatedSeptember 25, 1912
Government
  TypeMayor-council government
Area
  City
30.51 sq mi (79.01 km2)
  Land30.50 sq mi (79.00 km2)
  Water0.00 sq mi (0.01 km2)
Elevation
614 ft (187 m)
Population
 (2020)
  City
91,316
  Estimate 
(2023)
94,074
  Density2,993.67/sq mi (1,155.87/km2)
  Metro
2,810,056 (US: 19th)
Time zoneUTC−6 (CST)
  Summer (DST)UTC−5 (CDT)
ZIP code
63366, 63368
Area code636
FIPS code29-54074
GNIS feature ID2395303
Websitewww.ofallon.mo.us

O'Fallon (/ˈfælən/ oh-FAL-ən) is a city in St. Charles County, Missouri, United States. It is part of the St. Louis metropolitan statistical area, located along Interstates 64 and 70 between Lake St. Louis and St. Peters. As of the 2020 census, O'Fallon had a population of 91,316, making it the most populous suburb of St. Louis, as well as the most populous municipality in St. Charles County and the 7th most populous in Missouri. O'Fallon's namesake in St. Clair County, Illinois, is also part of the St. Louis region. The two cities are one of the few pairs of same-named municipalities to be part of the same metro area.