O'Fallon, Illinois

Coordinates: 38°35′46″N 89°54′56″W / 38.59611°N 89.91551°W / 38.59611; -89.91551
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O'Fallon, Illinois
The Illinois Central Railroad Downtown Caboose
The Illinois Central Railroad Downtown Caboose
Flag of O'Fallon, Illinois
Official seal of O'Fallon, Illinois
Official logo of O'Fallon, Illinois
Location of O'Fallon in St. Clair County, Illinois.
Location of O'Fallon in St. Clair County, Illinois.
Coordinates: 38°35′46″N 89°54′56″W / 38.59611°N 89.91551°W / 38.59611; -89.91551
Country United States
State Illinois
CountySt. Clair
 • TypeHome rule[1]
 • MayorHerb Roach
 • Total15.71 sq mi (40.67 km2)
 • Land15.59 sq mi (40.39 km2)
 • Water0.11 sq mi (0.29 km2)
Elevation541 ft (165 m)
 • Total32,289
 • Density2,070.60/sq mi (799.48/km2)
Time zoneUTC−6 (CST)
 • Summer (DST)UTC−5 (CDT)
ZIP code(s)
Area code618
FIPS code17-55249
GNIS feature ID2395302[3]
Wikimedia CommonsO'Fallon, Illinois

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 of the St. Louis metropolitan area and Southern Illinois. It sits 5 miles (8.0 km) from Scott Air Force Base and 18 miles (29 km) from Downtown St. Louis.

Like its namesake in St. Charles County, Missouri, O'Fallon is part of the St. Louis metro 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 metro region.


O'Fallon, 1938

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.

Tornado damage, 2006

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:[4]

"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."



O'Fallon is located at 38°35′N 89°54′W / 38.583°N 89.900°W / 38.583; -89.900 (38.591549, −89.912000).[5] O'Fallon is:

According to the 2010 census, the city has a total area of 14.48 square miles (37.5 km2), of which 14.35 square miles (37.2 km2) (or 99.10%) is land and 0.12 square miles (0.31 km2) (or 0.83%) is water.[6]


Historical population
U.S. Decennial Census[7]
2018 Estimate[8]

As of the census[9] of 2020, there were 32,289 people, 12,093 households, and 7,114 families living in the city. The population density was 2,959/sq mi (1,142/km2). There were 13,225 housing units at an average density of 1,158/sq mi (447/km2). The racial makeup of the city was 70.59% White, 16.38% African American, 0.22% Native American, 2.75% Asian, 0.10% Pacific Islander, 1.44% from other races, and 8.52% from two or more races. Hispanic or Latino of any race were 4.49% of the population.

Of the 12,093 households, 39.5% had children under the age of 18 living with them, 58.8% were married couples living together, 23.8% had a female householder with no spouse/partner present, and 13.3% had a male householder with no spouse/partner present. 23.1% of households were made up of individuals and 51.9% were one person aged 65 or older. The average household size was 2.65 and the average family size was 3.10.

The city’s age distribution consisted of 28.2% under the age of 18, 6.4% from 18 to 24, 37.6% from 15 to 44, 12.3% from 45 to 64, and 15.5% 65 or older. The median age was 37.3 years. For every 100 females, there were 96.1 males.

The median household income was $102,560 and the median family income was $123,695. The per capita income for the city was $44,647. About 4.2% of families and 3.3% of the population were below the poverty line, including 4.5% of those under age 18 and 3.1% of those age 65 or over.

Annual events[edit]

  • May - Memorial Day To Honor Those Who Gave their lives in service of the nation (O'Fallon Veterans Monument)[10]
  • 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 recreation[edit]

Rock Springs Nature Park
Public Library

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


  • O'Fallon Public Library

Registered historic places


Delores Moye School
  • 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

Private schools

  • Discovery School
  • St. Clare Catholic School
  • First Baptist Academy

Notable people[edit]



  1. ^ "Form of Government City of O'Fallon". City of O'Fallon, IL. Retrieved December 13, 2019.
  2. ^ "2020 U.S. Gazetteer Files". United States Census Bureau. Retrieved March 15, 2022.
  3. ^ a b U.S. Geological Survey Geographic Names Information System: O'Fallon, Illinois
  4. ^ O'Fallon Historical Society (2004). O'Fallon Sesquicentennial History.
  5. ^ "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. February 12, 2011. Retrieved April 23, 2011.
  6. ^ "2010 Census U.S. Gazetteer Files for Places – Illinois". United States Census. Retrieved October 13, 2012.
  7. ^ United States Census Bureau. "Census of Population and Housing". Retrieved May 13, 2015.
  8. ^ "Population Estimates". United States Census Bureau. Retrieved June 8, 2018.
  9. ^ "Explore Census Data". data.census.gov. Retrieved January 23, 2024.
  10. ^ "Calendar | City of OFallon, IL".

External links[edit]