The Chicago and Eastern Illinois Railroad was a Class I railroad that linked Chicago to southern Illinois, St. Louis, and Evansville. Founded in 1877, it grew aggressively and stayed relatively strong throughout the Great Depression and two World Wars before being purchased by the Missouri Pacific Railroad (MP, or MoPac) and the Louisville and Nashville Railroad (L&N). MoPac merged the C&EI corporate entity in 1976 and was later acquired itself by the Union Pacific Railroad.