U.S. Circuit Court, Northern District of Illinois
In 1855, Congress divided Illinois into two judicial districts—the Northern District of Illinois, which held court in Chicago, and the Southern District of Illinois, which held court in Springfield. The federal circuit courts had concurrent jurisdiction with the state courts over all cases in common law or equity where the matter in dispute exceeded $500, and jurisdiction in cases where the United States was a plaintiff, and in cases between citizens of different states.
“An Act to Divide the State of Illinois into Two Judicial Circuits,” 13 February 1855, Statutes at Large of the United States 10 (1855):606-7; “Court Structure,” in Martha L. Benner and Cullom Davis et al., eds., The Law Practice of Abraham Lincoln: Complete Documentary Edition, 2d edition (Springfield: Illinois Historic Preservation Agency, 2009), http://www.lawpracticeofabrahamlincoln.org/Reference.aspx?ref=Reference html files/Court Structure.html.