St. Clair County
St. Clair County Courthouse in Belleville
Flag of St. Clair County
Official seal of St. Clair County
Map of Illinois highlighting St. Clair County
Location within the U.S. state of Illinois
Map of the United States highlighting Illinois
Illinois's location within the U.S.
Coordinates: 38°28′N 89°56′W / 38.47°N 89.93°W / 38.47; -89.93
Country United States
State Illinois
Named forArthur St. Clair
Largest cityBelleville
 • Total674 sq mi (1,750 km2)
 • Land658 sq mi (1,700 km2)
 • Water16 sq mi (40 km2)  2.4%
 • Total257,400
 • Density380/sq mi (150/km2)
Time zoneUTC−6 (Central)
 • Summer (DST)UTC−5 (CDT)
Congressional district12th
House in Lebanon, Il historic district
House in Lebanon, Il historic district
Mermaid House Hotel, Lebanon, Illinois
Mermaid House Hotel, Lebanon, Illinois

St. Clair County is the oldest county in Illinois; its western border is formed by the Mississippi River, bordering Missouri. It is a part of the Metro East in southern Illinois. According to the 2020 United States Census, it had a population of 257,400, making it the eighth-most populous county in Illinois and the most populous in the southern portion of the state. Its county seat is Belleville.[1] The county was founded in 1790 by the government of the Northwest Territory, from the western half of Knox County, before the establishment of Illinois as a state as the base for the Illinois Territory. Cahokia Village in the county was founded in 1697 and was a French settlement and former Jesuit mission.

St. Clair County is part of the American Bottom or Metro-East area of the St. Louis, MO-IL Metropolitan Statistical Area.

In 1970, the United States Census Bureau placed the mean center of U.S. population in St. Clair County.[2]


This area was occupied for thousands of years by cultures of indigenous peoples. The first modern explorers and colonists of the area were French and French Canadians, founding a mission settlement in 1697 now known as Cahokia Village. After Great Britain defeated France in the Seven Years' War in 1763 and absorbed its territory in North America east of the Mississippi River, British-American colonists began to move into the area. Many French Catholics moved to settlements west of the river rather than live under British Protestant rule.

After the United States achieved independence in the late 18th century, St. Clair County was the first county established in present-day Illinois; it antedates Illinois' existence as a separate jurisdiction. The county was established in 1790 by a proclamation of Arthur St. Clair, first governor of the Northwest Territory, who named it after himself.

The original boundary of St. Clair county covered a large area between the Mackinaw and Ohio rivers. In 1801, Governor William Henry Harrison re-established St. Clair County as part of the Indiana Territory, extending its northern border to Lake Superior and the international border with Rupert's Land.[3]

When the Illinois Territory was created in 1809, Territorial Secretary Nathaniel Pope, in his capacity as acting governor, issued a proclamation establishing St. Clair and Randolph County as the two original counties of Illinois.

Originally developed for agriculture, this area became industrialized and urbanized in the area of East St. Louis, Illinois, a city that developed on the east side of the Mississippi River from St. Louis, Missouri. It was always strongly influenced by actions of businessmen from St. Louis, who were initially French Creole fur traders with western trading networks.

In the 19th century, industrialists from St. Louis put coal plants and other heavy industry on the east side of the river, developing East St. Louis. Coal from southern mines was transported on the river to East St. Louis, then fed by barge to St. Louis furnaces as needed. After bridges spanned the river, industry expanded.

In the late 19th and early 20th centuries, the cities attracted immigrants from southern and eastern Europe and from the South. In 1910 there were 6,000 African Americans in the city. With the Great Migration underway from the rural South, to leave behind Jim Crow and disenfranchisement, by 1917, the African-American population in East St. Louis had doubled. Whites were generally hired first and given higher–paying jobs, but there were still opportunities for American blacks. If hired as strikebreakers, they were resented by white workers, and both groups competed for jobs and limited housing in East St. Louis. The city had not been able to keep up with the rapid growth of population. The United States was developing war industries to support its eventual entry into the Great War, now known as World War I.

Main article: East St. Louis riots

In February 1917 tensions in the city arose as white workers struck at the Aluminum Ore Company. Employers fiercely resisted union organizing, sometimes with violence. In this case they hired hundreds of blacks as strikebreakers. White workers complained to the city council about this practice in late May. Rumors circulated about an armed African American man robbing a white man, and whites began to attack blacks on the street. The governor ordered in the National Guard and peace seemed restored by early June.

"On July 1, a white man in a Ford shot into black homes. Armed African-Americans gathered in the area and shot into another oncoming Ford, killing two men who turned out to be police officers investigating the shooting."[4] Word spread and whites gathered at the Labor Temple; the next day they fanned out across the city, armed with guns, clubs, anything they could use against the blacks they encountered. From July 1 through July 3, 1917, the East St. Louis riots engulfed the city, with whites attacking blacks throughout the city, pulling them from streetcars, shooting and hanging them, burning their houses. During this period, some African Americans tried to swim or use boats to get to safety; thousands crossed the Eads Bridge to St. Louis, seeking refuge, until the police closed it off. The official death toll was 39 blacks and nine whites, but some historians believe more blacks were killed.[4] Because the riots were racial terrorism, the Equal Justice Initiative has included these deaths among the lynchings of African Americans in the state of Illinois in its 2017 3rd edition of its report, Lynching in America.[5]

The riots had disrupted East St. Louis, which had seemed to be on the rise as a flourishing industrial city. In addition to the human toll, they cost approximately $400,000 in property damage[6] (over $8 million, in 2017 US Dollars [7]). They have been described as among the worst labor and race-related riots in United States history, and they devastated the African-American community.

Rebuilding was difficult as workers were being drafted to fight in World War I. When the veterans returned, they struggled to find jobs and re-enter the economy, which had to shift down to peacetime.

In the late 20th century, national restructuring of heavy industry cost many jobs, hollowing out the city, which had a marked decline in population. Residents who did not leave have suffered high rates of poverty and crime. In the early 21st century, East St. Louis is a site of urban decay. Swathes of deteriorated housing were demolished and parts of the city have become urban prairie. In 2017 the city marked the centennial of the riots that had so affected its residents.

Other cities in St. Clair County border agricultural or vacant lands. Unlike the suburbs on the Missouri side of the metro area, those in Metro-East are typically separated by agriculture, or otherwise undeveloped land left after the decline of industry. The central portion of St. Clair county is located on a bluff along the Mississippi River. This area is being developed with suburban housing, particularly in Belleville, and its satellite cities. The eastern and southern portion of the county is sparsely populated. The older small communities and small tracts of newer suburban villages are located between large areas of land devoted to corn and soybean fields, the major commodity crops of the area.


According to the US Census Bureau, the county has a total area of 674 square miles (1,750 km2), of which 658 square miles (1,700 km2) is land and 16 square miles (41 km2) (2.4%) is water.[8]

Climate and weather

Belleville, Illinois
Climate chart (explanation)
Average max. and min. temperatures in °F
Precipitation totals in inches
Source: The Weather Channel[9]

In recent years, average temperatures in the county seat of Belleville have ranged from a low of 22 °F (−6 °C) in January to a high of 90 °F (32 °C) in July, although a record low of −27 °F (−33 °C) was recorded in January 1977 and a record high of 117 °F (47 °C) at East St. Louis, Illinois was recorded in July 1954.[10][11][12] Average monthly precipitation ranged from 2.02 inches (51 mm) in January to 4.18 inches (106 mm) in May.[9]


Major highways

Public transit

St. Clair County is home to 11 St. Louis MetroLink stations on the Red and Blue Lines.

St. Clair County is also served by Metrobus and Madison County Transit.

Adjacent counties and city


Historical population
Census Pop.
US Decennial Census[13]
1790-1960[14] 1900-1990[15]
1990-2000[16] 2010-2019[17]

In the 2020 United States Census the racial makeup of the county was 59.6% White, 29.7% black or African American, 1.4% Asian, 0.3% American Indian, 0.1% Pacific islander, 2.1% from other races, and 6.8% from two or more races. 4.9% were of Hispanic or Latino origin.[18]

As of the 2010 United States Census, there were 270,056 people, 105,045 households, and 70,689 families residing in the county.[19] The population density was 410.6 inhabitants per square mile (158.5/km2). There were 116,249 housing units at an average density of 176.7 per square mile (68.2/km2).[8] The racial makeup of the county was 64.6% white, 30.5% black or African American, 1.2% Asian, 0.2% American Indian, 0.1% Pacific islander, 1.2% from other races, and 2.2% from two or more races. Those of Hispanic or Latino origin made up 3.3% of the population. In terms of ancestry, 27.5% were German, 11.1% were Irish, 7.4% were English, and 4.6% were American.[20]

Of the 105,045 households, 34.7% had children under the age of 18 living with them, 44.6% were married couples living together, 17.7% had a female householder with no husband present, 32.7% were non-families, and 27.5% of all households were made up of individuals. The average household size was 2.53 and the average family size was 3.09. The median age was 36.9 years.

The median income for a household in the county was $48,562 and the median income for a family was $61,042. Males had a median income of $47,958 versus $34,774 for females. The per capita income for the county was $24,770. About 12.3% of families and 15.5% of the population were below the poverty line, including 24.7% of those under age 18 and 9.7% of those age 65 or over.[21]

Government and infrastructure

The Southwestern Illinois Correctional Center, operated by the Illinois Department of Corrections, is near East St. Louis.[22]

Also located in St. Clair County is Scott Air Force Base, which is home to U.S. Transportation Command, the Air Force's Air Mobility Command, and the Military Surface Deployment and Distribution Command.


St. Clair County is a reliably Democratic county, having voted for the Democratic presidential candidate in every presidential election since 1928, with the exception of the 1972 United States presidential election.

United States presidential election results for St. Clair County, Illinois[23]
Year Republican Democratic Third party
No.  % No.  % No.  %
2020 57,150 44.62% 68,325 53.34% 2,616 2.04%
2016 53,857 44.35% 60,756 50.03% 6,823 5.62%
2012 50,125 41.83% 67,285 56.15% 2,417 2.02%
2008 47,958 38.05% 76,160 60.42% 1,936 1.54%
2004 50,203 44.35% 62,410 55.14% 576 0.51%
2000 42,299 42.13% 55,961 55.74% 2,133 2.12%
1996 33,066 35.02% 53,405 56.56% 7,958 8.43%
1992 31,951 29.71% 57,625 53.58% 17,965 16.71%
1988 41,439 42.58% 55,465 57.00% 409 0.42%
1984 51,046 49.01% 52,294 50.21% 808 0.78%
1980 46,063 45.76% 50,046 49.71% 4,564 4.53%
1976 40,333 39.91% 59,177 58.55% 1,555 1.54%
1972 50,519 51.50% 46,636 47.54% 942 0.96%
1968 34,442 34.14% 50,726 50.29% 15,706 15.57%
1964 28,226 27.61% 74,005 72.39% 0 0.00%
1960 42,046 38.31% 67,367 61.38% 338 0.31%
1956 41,528 42.77% 55,295 56.94% 283 0.29%
1952 39,713 39.51% 60,311 60.01% 479 0.48%
1948 30,883 36.07% 54,260 63.38% 474 0.55%
1944 33,557 40.82% 48,325 58.78% 327 0.40%
1940 35,998 40.05% 53,482 59.50% 411 0.46%
1936 26,684 31.86% 54,238 64.75% 2,840 3.39%
1932 22,744 31.34% 47,305 65.18% 2,522 3.48%
1928 31,026 45.60% 36,374 53.46% 637 0.94%
1924 23,380 45.85% 14,921 29.26% 12,693 24.89%
1920 21,681 51.34% 14,032 33.23% 6,518 15.43%
1916 22,134 47.70% 22,622 48.75% 1,650 3.56%
1912 8,156 31.53% 10,826 41.85% 6,884 26.61%
1908 12,619 48.66% 11,342 43.73% 1,973 7.61%
1904 11,926 55.31% 8,200 38.03% 1,435 6.66%
1900 9,764 48.67% 9,827 48.98% 472 2.35%
1896 8,960 50.96% 8,345 47.46% 278 1.58%
1892 6,276 44.72% 7,207 51.35% 551 3.93%




Census-designated places

Unincorporated communities


Former Township

Former Communities



Here is a list of school districts with any territory in the county, no matter how slight, even if the schools and/or administrative offices are located in other counties:[25]

K-12 school districts
Secondary school districts
Elementary school districts

See also


  1. ^ "Find a County". National Association of Counties. Retrieved June 7, 2011.
  2. ^ "Mean Center of Population for the United States: 1790 to 2000" (PDF). US Census Bureau. Archived from the original (PDF) on November 3, 2001. Retrieved September 17, 2011.
  3. ^ a b White, Jesse. Origin and Evolution of Illinois Counties. State of Illinois, March 2010. [1]
  4. ^ a b Alison Keyes, "The East St. Louis Race Riot Left Dozens Dead, Devastating a Community on the Rise", Smithsonian Magazine, 30 June 2017; accessed 26 May 2018
  5. ^ "Lynching in America/Supplement by County, 3rd ed. (2017) p. 4" (PDF). Archived from the original (PDF) on October 23, 2017. Retrieved July 5, 2018.
  6. ^ "The Negro Silent Protest Parade organized by the NAACP Fifth Ave., New York City July 28, 1917" (PDF). National Humanities Center, Research Triangle Park, NC. National Humanities Center. 2014. Retrieved July 28, 2017.
  7. ^ "Calculate the value of $400,000 in 1917".
  8. ^ a b "Population, Housing Units, Area, and Density: 2010 - County". US Census Bureau. Archived from the original on February 12, 2020. Retrieved July 12, 2015.
  9. ^ a b "Monthly Averages for Belleville IL". The Weather Channel. Retrieved January 27, 2011.
  10. ^ Westcott, Nancy E. (July 2011). "The Prolonged 1954 Midwestern US Heat Wave: Impacts and Responses". Wea. Climate Soc. 3 (3): 165–76. doi:10.1175/WCAS-D-10-05002.1.
  11. ^ "Lessons Learned from 1950s' Heat Wave Show Planning Needed for Future Severe Events" (Press release). Illinois State Water Survey. May 18, 2011. Archived from the original on April 15, 2012. Retrieved November 4, 2011.
  12. ^ Westcott, Nancy (January 19, 2010). "Impacts of the 1954 Heat Wave". 18th Conference on Applied Climatology. Atlanta GA: American Meteorological Society.
  13. ^ "US Decennial Census". US Census Bureau. Retrieved July 8, 2014.
  14. ^ "Historical Census Browser". University of Virginia Library. Retrieved July 8, 2014.
  15. ^ "Population of Counties by Decennial Census: 1900 to 1990". US Census Bureau. Retrieved July 8, 2014.
  16. ^ "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). US Census Bureau. Retrieved July 8, 2014.
  17. ^ "State & County QuickFacts". US Census Bureau. Archived from the original on June 7, 2011. Retrieved July 8, 2014.
  18. ^ "St. Clair County, Illinois". US Census Bureau. Retrieved January 9, 2020.
  19. ^ "Profile of General Population and Housing Characteristics: 2010 Demographic Profile Data". US Census Bureau. Archived from the original on February 13, 2020. Retrieved July 12, 2015.
  20. ^ "Selected Social Characteristics in the United States – 2006-2010 American Community Survey 5-Year Estimates". US Census Bureau. Archived from the original on February 13, 2020. Retrieved July 12, 2015.
  21. ^ "Selected Economic Characteristics – 2006-2010 American Community Survey 5-Year Estimates". US Census Bureau. Archived from the original on February 13, 2020. Retrieved July 12, 2015.
  22. ^ Southwestern Illinois Correctional Center. IL Dept of Corrections. Retrieved on July 10, 2010.
  23. ^ Leip, David. "Atlas of US Presidential Elections". Retrieved March 27, 2018.
  24. ^ "Belleville officially takes over township's duties". Retrieved March 27, 2018.
  25. ^ "2020 CENSUS - SCHOOL DISTRICT REFERENCE MAP: St. Clair County, IL" (PDF). U.S. Census Bureau. Retrieved July 19, 2022. - Text list

Coordinates: 38°28′N 89°56′W / 38.47°N 89.93°W / 38.47; -89.93