16 (from 6 confederations) were the number of teams who competed in Chicago Marathon . 18 from 18 nations were the competitors in Chicago Marathon . It was held in 28 July – 9 August . The venue for Chicago Marathon was London Velopark (BMX, track),Chicago, Illinois, United States . The sport has the official site www.hardrock100.com . 1891; 128 years ago (1891) is when Chicago Marathon was founded 
Chicago Marathon happened in multiple place