Saint Clair County , Illinois

Saint Clair County: The County of St. Clair is the oldest county in the U. S. Illinois state; the Mississippi River, bordering the U, forms its western boundary. S. Missouri State. In southern Illinois, it is part of the Metro East. It had a population of 270,056 according to the 2010 United States Census, making it the eighth-most populous county in Illinois and the most populous in the state's southern part. Its seat in the county is Belleville.

Saint Clair County locator map
Location of Saint Clair County on Illinois map.

About

Saint Clair County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 270,056 and a population density of 155 people per km². After 10 years in 2020 county had an estimated population of 258,046 inhabitants. Its county seat is Belleville. The county was created 231 years ago in 1790.

Downtown Belleville Illinois Courthouse image
Downtown Belleville Illinois Courthouse
Downtown Belleville Illinois Courthouse image

Geography

Saint Clair County is located at 38°28'13"N 89°55'42"W (38.4703100, -89.9284100). It has 2 neighbors: Monroe County and Randolph County.

Saint Clair County map

The largest city of Saint Clair County is Belleville with a population of 40,536. Other cities include, East Saint Louis population 25,776, Crest Hill population 20,209, Fairview Heights population 16,127 and Pontiac population 11,176. See all Saint Clair County cities & populated places.

Saint Clair County Quick Facts

Population : 258,046 (2020)
Country : United States of America
State : Illinois (United States)
Different from : St. Clair County, St. Clair County, St. Clair County
Area : 1746 km2
Water as percent of area : 2.4%
Land as percent of area : 97.6%
Named for : Arthur St. Clair
Capital : Belleville
Establishment : April 04, 1790
Time Zone : America/Chicago
Local time : 11:59:19 (24th October 2021)
Density : 148 Pop. per km² as of 2020
Population growth : -4.65% (2010-2020)

Saint Clair County has 2 neighbours.

Demographics

According to census records, the population of Saint Clair County decreased by 4.65% in 10 years.

Year Population % Change Method
2010 270,056 - census
2011 270,048 -0% estimation process
2012 268,673 -0.51% estimation process
2013 266,831 -0.69% estimation process
2014 265,941 -0.33% estimation process
2015 264,858 -0.41% estimation process
2016 263,187 -0.63% estimation process
2017 262,600 -0.22% estimation process
2018 261,360 -0.47% estimation process
2019 259,686 -0.64% estimation process
2020 258,046 -0.64% estimation process

Comte de Saint Clair, Comté de Saint Clair, Saint Clair

People born in Saint Clair County (4)

People born in Saint Clair County, including baseball player Neal Cotts, artist Paul Soldner, politician Charles A. Karch, you can see a list of people who born in Saint Clair County.

Other places with the same name (4)

Saint Clair County Populated Places (more)

Cities, Towns, Neighborhoods & Other Populated Places in Saint Clair County.

City Name Population Title
Glenview 46,823 Village in Cook County, Illinois, United States
Belleville 40,536 City in Illinois
O'Fallon 29,606 Township in St.
East Saint Louis 25,776 City in St.
Crest Hill 20,209 City in Will County, Illinois
Fairview Heights 16,127 City in Saint Clair County, Illinois, United States
Cahokia 13,742 Village in St.
Shiloh 13,653 Town in St.
Swansea 13,276 Village in St.
Pontiac 11,176 City in Illinois, USA
Summit 10,977 Village in Illinois, USA
Mascoutah 8,076 City in Saint Clair County, Illinois, United States
Centreville 4,844 City in Illinois, United States
Lebanon 4,225 City in St.
Freeburg 4,223 City in Illinois, United States of America
Rosemont 4,147 Village in the U.

Illinois Other Counties (more counties)

County Name Population Title
Cook County 5,108,284 County in Illinois, United States
Chicago 2,677,643 City and county seat of Cook County, Illinois, United States
DuPage County 917,481 County in Illinois, United States
Lake County 693,593 County in Oregon, United States
Will County 688,726 County in Illinois, United States
Kane County 531,010 County in southern Utah, United States
Markham 328,966 City in Cook County, Illinois, United States
McHenry County 305,888 County in Illinois, United States
Winnebago County 281,295 County in Illinois, United States
Madison County 262,635 County in Montana, United States
Champaign County 209,192 County in Illinois, United States
Aurora 196,383 City in Kane County, Illinois, United States
Sangamon County 193,882 County in Illinois, United States
Peoria County 177,652 County in Illinois, United States of America
McLean County 171,256 County in North Dakota, United States
Naperville 147,986 City in DuPage and Will counties in Illinois, United States