Cahokia Courthouse State Historic Site
A Confluence Attraction

(618) 332-1782

Participating Confluence Organization
Illinois Historic Preservation Agency

Wednesday through Sunday 9:00 a.m to 5:00 p.m.
Closed on major and federal holidays; check website.

First and Elm Streets
Cahokia IL 62206

(By car) From I-55/70 in Illinois (reached from downtown St. Louis via the Poplar Street Bridge), exit Illinois Route 3 South and proceed three miles to Illinois Route 157. The courthouse is located next to this intersection.
(By bike) From the Cargill Road terminus of the Metro-East Levee Trail, proceed East on Cargill Road, approximately 1/2 mile to the courthouse.

The Courthouse was originally constructed as a dwelling around 1730, during a period when Cahokia was rapidly becoming the largest of the French colonial towns in the Mississippi Valley, thanks to its role as a major trade center in furs and Indian goods. Cahokia and the Illinois Country were ceded to Great Britain after the French and Indian War of 1763, and surrendered to United States forces in 1778. In 1787, the town was named a county seat and the family structure was purchased to serve as the Courthouse, a role it fulfilled for the next 24 years. As William Clark prepared for his expedition through the Louisiana Territory, he corresponded with Thomas Jefferson from the Courthouse, and met there with Meriwether Lewis and territorial leaders.

Floods often threatened the Courthouse site, causing the relocation of the county seat to higher ground in Belleville in 1814. Thereafter, the former Courthouse endured much neglect and many uses, including storehouse and saloon. The deteriorated structure was purchased for display (greatly modified) at the 1904 World’s Fair, and auctioned afterward to the Chicago Historical Society for public display. After a long campaign by Cahokians to regain what remained of the building, it was finally acquired by the state in 1936. Archeological investigations of its original site, aided by study of building sketches and similar construction in the area, permitted a careful reconstruction and rededication of the courthouse in 1940.

The Cahokia Courthouse is an excellent example of early French colonial post-on-sill log construction, with stone and mortar chinking and a cantilevered roof over the porch. The building rests on its original stone foundation, nearly two feet thick. The interior’s four rooms originally functioned as a courtroom, a schoolroom and offices for attorneys and clerks.

An exhibit in the building relates to Lewis and Clark’s experiences in the Cahokia area.

Located within easy walk of two other French colonial sites in Cahokia, the Church of the Holy Family and the Jarrot Mansion (both have entries on this website).

For more information about the Cahokia Courthouse and nearby French Colonial sites, see

For more information about other nearby attractions, see