 The Chicago Marathon is a major marathon held yearly in Chicago in Cook County , Illinois , United States . Alongside the Boston , New York , London , Berlin , and Tokyo Marathons , it is one of the six World Marathon Majors . Thus , it is also an IAAF Gold Label race . The October 9 , 2016 running will be the 39th anniversary of the race . The first race was held on September 25 , 1977 under the original name the Mayor Daley Marathon , which drew a field of 4 @,@ 200 runners . The race has been held every year since , except in 1987 when only a half @-@ marathon was run . It is among the fastest growing marathon road races in the world , due in part to its largely fast and flat course which facilitates the pursuit of personal records and world record performances . The race has achieved its elite status among marathons by developing relationship with sponsors who provide prize money to lure elite runners who have produced American and world record performances . Since 2008 the race has been sponsored by Bank of America , and is officially known as the Bank of America Chicago Marathon . 
