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 ==Geography==