The Chicago Marathon is a marathon (long-distance foot race) held every October in Chicago, Illinois. It is one of the seven World Marathon Majors. It is also a World Athletics Label Road Race.
The Chicago Marathon is the fourth-largest race by number of finishers worldwide, with around 50,000 runners entered each year.
Since 2008, the race has been owned and organized by Bank of America, and is officially known as the Bank of America Chicago Marathon.