[1] Cahokia Village was founded in 1697 by French settlers and served as a Jesuit mission to convert tribes of the Illinois Confederation to Christianity.

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

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.

The original boundary of St. Clair county covered a large area between the Mackinaw and Ohio rivers.

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 late 19th and early 20th centuries, the cities attracted immigrants from southern and eastern Europe and from the South.

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.

If hired as strikebreakers, they were resented by white workers, and both groups competed for jobs and limited housing in East St. Louis.

In February 1917 tensions in the city arose as white workers struck at the Aluminum Ore Company.

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.

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.

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.

In the late 20th century, national restructuring of heavy industry cost many jobs, hollowing out the city, which had a marked decline in population.

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.