The official site of Chicago Marathon is www.hardrock100.com . The no. of events in sport was 18 . The venue for Chicago Marathon was Tennis Club de Paris, at Auteuil (some of the years 1895–1908),Chicago, Illinois, United States,Arena Olímpica do Rio . 37 from 31 nations were the competitors in Chicago Marathon . 19–20 August was when it was held . 12 were the number of teams who competed in Chicago Marathon . Chicago Marathon was established on 1891; 128 years ago (1891)
In the sport Chicago Marathon ,31 nations participated