Chicago Marathon was established on 1891; 128 years ago (1891) . It was held in 28 July – 9 August . 18 from 18 nations competed in Chicago Marathon . The venue for Chicago Marathon was London Velopark (BMX, track),Chicago, Illinois, United States . 16 (from 6 confederations) were the number of teams who competed in Chicago Marathon . The sport has the official site www.hardrock100.com
The sport Chicago Marathon has less than29 contenders  from less than 20 nations