The Chicago Marathon route, printed

Chicago begins and ends in Grant Park and loops north, west and south through the city on roads so flat that its one named hill is a short rise a few hundred metres from the finish.

The flatness is what makes Chicago fast, and in 2023 Kelvin Kiptum ran a men's world record here. It also makes the opening miles deceptive. The field crosses the river twice in the first few miles through the Loop, where the tall buildings confuse GPS watches, then runs north on LaSalle Street through River North and Old Town into Lincoln Park, past the zoo. From Belmont Avenue the course follows Inner Lake Shore Drive to its northernmost point at around mile 8 in Lakeview, before turning back south down Broadway through Northalsted.

The return comes through Old Town again and over the river on Wells Street, and halfway falls on the edge of the Loop. The second half is the city's neighbourhoods one after another. The course goes west on Adams Street through the West Loop and Greektown as far as Damen Avenue, then turns back east and south into Little Italy on Taylor Street and Pilsen on 18th Street. Chinatown comes at around mile 21, with an almost complete about-turn at the Chinatown Gate, and Bronzeville marks the southern end of the course on 35th Street.

From there it is a long, straight run north up Michigan Avenue with the skyline growing ahead. After the mile 26 marker the course turns onto Roosevelt Road for the short climb the organisers call Mount Roosevelt, then left onto Columbus Drive for the finish in Grant Park. The race was first held in 1977, and October weather here can turn either way: in 2007 the temperature reached 31°C by mid-morning, and organisers shut the course about four hours in, with runners still out on it told to walk.