The Legal Reports record group is a very diverse amalgam, including not only legal reports but also Annual Reports of the company, statements and miscellaneous reports, contracts with vendors and other rail lines, tax papers, and documents on various subjects (Civil War settlements, Cairo, Illinois, the Chicago Lake Front, and the Tripartite Agreement with New Orleans, Jackson & Great Northern RR and the Mississippi Central and Southern Railroad Association). This record group also includes published material that may have been out of scope in any other record group: printed circulars, newspaper clippings, and papers used in preparing historical summaries of the Illinois Central RR.

Of note in this record group is a collection of scrapbooks kept by former administrator and President William K. Ackerman. These scrapbooks detail his family history and the history of early Chicago and Chicago's World's Columbian Exposition of 1893.