Old Cahokia Courthouse - The American Bottom

The American Bottom

Following the American Revolution and the Treaty of Paris in 1783, the Cahokia region was transferred with the rest of the east bank of the Mississippi from Great Britain to the new United States. The alluvial region east of the river came to be known as the American Bottom, to distinguish it from the west bank of the river, at that time a colony of Spain.

The American frontiersmen were jealous of their right to govern themselves in local communities, and invested a substantial amount of their very limited resources to set up a legal infrastructure of local self-government. On April 27, 1790, St. Clair County, Illinois, the first county located within the Illinois region of the Northwest Territory, was organized. Soon afterwards, the 1740 Cahokia house, an unusually well-built structure, was promoted to the status of a courthouse for the new county.

Territorial law books describe the kind of decisions and court cases that were made and heard in this small building. Tangled French-American land titles were unsnarled here. Certain types of businesses, such as frontier taverns and ferryboats, required licenses that were issued from this building. Criminal cases were heard, and votes were counted.

In 1804 the federal government opened its first Illinois land office, in Kaskaskia, to sell former Native American land to settlers. Soon the population of St. Clair County grew far too large for the small log cabin to be adequate as a courthouse.