In 1819, Vandalia up the river in the interior of the then new state of Illinois was chosen as its capital, which it served as until 1839.

[citation needed] It was named after a clan of the Illiniwek encountered by the early French Jesuits and other settlers.

The Kaskaskia rises in east central Illinois in several farm ditches along the west side of Champaign.

The river flows south across rural Champaign and Douglas counties, then southwest across southern Illinois, past Vandalia.

Deforestation of river banks of the Mississippi and tributaries to fuel the hundreds of steamboats that plied the river had several significant environmental effects: destabilizing the banks, causing the Mississippi to become wider and more shallow, causing more severe flooding and leading to lateral channel changes in the American Bottoms area.