kids encyclopedia robot

O'Fallon, Illinois facts for kids

Kids Encyclopedia Facts
Quick facts for kids
O'Fallon, Illinois
City of O’Fallon
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.
Location of Illinois in the United States
Location of Illinois in the United States
Country United States
State Illinois
County St. Clair
Township O'Fallon
 • Type Home rule
 • Total 15.48 sq mi (40.08 km2)
 • Land 15.37 sq mi (39.79 km2)
 • Water 0.11 sq mi (0.29 km2)
 • Total 32,289
 • Estimate 
 • Density 1,925.35/sq mi (743.40/km2)
Time zone UTC−6 (CST)
 • Summer (DST) UTC−5 (CDT)
ZIP code(s)
Area code(s) 618
FIPS code 17-55249
Wikimedia Commons O'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 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 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.


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 year except 1930, when the census showed a net loss of six residents.

Tornado Damage, Illinois 2
Tornado damage, 2006

Growth in O'Fallon has accelerated since the 1980s. Following the expansion of Interstate 64, the 1990s saw a building boom with the construction of several now-established subdivisions including Thornbury Hills, Nolin Creek Estates, Fairwood Hills, Deer Creek, Forest Hills, and the completion of 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. A new city hall was completed in 1996. More than 50 percent of O'Fallon's housing is less than 15 years old.


  • April 2, 2006 Central United States tornado outbreak

Annual events

    • May - Memorial Day To Honor Those Who Gave their lives in service of the nation (O'Fallon Veterans Monument)
    • November – Craft Fair; Veterans Day Celebration at O'Fallon Veterans Monument

Parks and recreation

Rock Springs nature center, O'Fallon, Illinois (2006)
Rock Springs Nature Park
OFallon Public Library
Public Library
  • Family Sports Park
  • Hesse Park
  • Katy Cavin's Community Center
  • O'Fallon Community Park
  • Rock Springs Nature Park
    • Nature center
    • Jogging/cycling paths
    • Nature trails
    • Natural prairie
    • Dog Park
  • St. Clair Recreation Complex
  • St. Ellen Mine Park
  • Thoman Park
  • Veteran's Monument

Registered historic places


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). 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.


Historical population
Census Pop.
1870 1,117
1880 921 −17.5%
1890 865 −6.1%
1900 1,267 46.5%
1910 2,018 59.3%
1920 2,379 17.9%
1930 2,373 −0.3%
1940 2,407 1.4%
1950 3,022 25.6%
1960 4,018 33.0%
1970 7,268 80.9%
1980 12,173 67.5%
1990 16,073 32.0%
2000 21,910 36.3%
2010 28,281 29.1%
2019 (est.) 29,583 4.6%
U.S. Decennial Census
2018 Estimate

As of the census of 2010, there were 28,281 people, 8,310 households, and 6,016 families living in the city. The population density was 1,970/sq mi (760/km2). There were 8,310 housing units at an average density of 580/sq mi (220/km2). The racial makeup of the city was 82.67% White, 11.99% African American, 0.23% Native American, 2.47% Asian, 0.07% Pacific Islander, 0.79% from other races, and 1.77% from two or more races. Hispanic or Latino of any race were 2.23% of the population.

Of the 8,310 households 39.6% had children under the age of 18 living with them, 59.0% were married couples living together, 10.5% had a female householder with no husband present, and 27.6% were non-families. 23.2% of households were one person and 7.2% were one person aged 65 or older. The average household size was 2.62 and the average family size was 3.13.

The age distribution was 28.3% under the age of 18, 8.0% from 18 to 24, 32.2% from 25 to 44, 22.7% from 45 to 64, and 8.9% 65 or older. The median age was 35 years. For every 100 females, there were 93.2 males. For every 100 females age 18 and over, there were 90.1 males.

The median household income was $55,927 and the median family income was $66,262. Males had a median income of $46,303 versus $30,158 for females. The per capita income for the city was $24,821. About 4.1% of families and 5.0% of the population were below the poverty line, including 5.0% of those under age 18 and 7.9% of those age 65 or over.


Notable people

Images for kids

kids search engine
O'Fallon, Illinois Facts for Kids. Kiddle Encyclopedia.