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 from Scott Air Force Base and from Downtown St Louis.
Like its namesake in St. Charles County, Missouri, O'Fallon is part of the St. Louis Metropolitan Statistical 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 MSA.
History
Founded in 1854, O'Fallon's namesake comes from Colonel John O'Fallon who was a wealthy gentleman from St. Louis. In downtown O'Fallon, a Baltimore and Ohio Railroad railroad depot was built, which helped put O'Fallon on the map. City lots were platted and sold at a public auction on May 18, 1854. A post office was established the following year and the city began attracting German settlers looking for fertile farming land. On January 27, 1874, O'Fallon was incorporated as a village. On March 14, 1905, the citizens voted for a change to the city form of government. Since its founding, O'Fallon has gained population every decennial census year except 1930, when the census showed a net loss of six residents.
The city center is approximately two miles east of the intersection of Interstate 64 and U.S. Route 50. Suburban growth in O'Fallon expanded considerably during the 1980s and following the expansion of Interstate 64 in the 1990s. Subdivisions include Thornbury Hill, Nolin Creek Estates, Fairwood Hills, Deer Creek, Forest Hills, and Fairwood East. O'Fallon Township High School's main campus at 600 South Smiley Street has undergone numerous additions over the past decades to ease overcrowding, including the creation of the separate 9th Grade Milburn Campus.
O'Fallon's city seal was designed in 1974 by Michael Donovan, an OTHS freshman, during a contest held by the O'Fallon Junior Woman's Club to create a city flag. In May 1975, the design was finalized by Louis Bradshaw and was then adopted by the city as its official flag. According to the 2004 publication by the O'Fallon Historical Society, O'Fallon Sesquicentennial History: "The design is yellow gold on a blue background—the colors of the high school. The pick and shovel represent the coal mines that were so important to O'Fallon's economy for over 100 years. The locomotive represents the railroad to which O'Fallon owes its existence. The planes represent Scott Air Force Base where many in O'Fallon find employment—both military and civil service."
Events
Tornado outbreak of April 2, 2006
Annual events
May - Memorial Day To Honor Those Who Gave their lives in service of the nation (O'Fallon Veterans Monument) November – Veterans Day Celebration at O'Fallon Veterans Monument; Veterans Day Parade - largest in the area November, the Saturday after Thanksgiving - Lighted Holiday Parade
Parks and public services
O'Fallon Parks and Recreation
Family Sports Park
Hesse Park
Katy Cavin's Community Center
O'Fallon Community Park
O'Fallon Memorial Pool
Rock Springs Nature Park
Nature center
Jogging/cycling paths
Nature trails
Natural prairie
Dog Park
MCT Goshen Trailhead
St. Clair Recreation Complex
St. Ellen Mine Park
Thoman Park
Veteran's Monument
Library
O'Fallon Public Library
Registered historic places
Scott Field Historic District
Schools
O'Fallon Community Consolidated School District #90
Delores Moye Elementary School
Estelle Kampmeyer Elementary School
J. E. Hinchcliffe Sr. Elementary School
Laverna Evans Elementary School
Marie Schaefer Elementary School
Amelia V. Carriel Junior High School
Edward A. Fulton Junior High School
O'Fallon Central School District #104
O'Fallon Township High School District No. 203
O'Fallon Township High School
Private schools
Discovery School
St. Clare Catholic School
First Baptist Academy
Geography
O'Fallon is located at (38.591549, −89.912000). O'Fallon is: from Scott Air Force Base from McKendree University and from St. Louis, Missouri According to the 2010 census, the city has a total area of , of which (or 99.10%) is land and (or 0.83%) is water.