12 teams competed in Chicago Marathon . 37 from 31 nations competed in Chicago Marathon . 1891; 128 years ago (1891) is when Chicago Marathon was established  . Tennis Club de Paris, at Auteuil (some of the years 1895–1908),Chicago, Illinois, United States,Arena Olímpica do Rio were the venues of Chicago Marathon . The official site of Chicago Marathon is www.hardrock100.com . 19–20 August was when it was held . 18 events were there in Chicago Marathon
Chicago Marathon happened in multiple place