Among the streets closed by the race are Columbus Drive, Grand Avenue, State Street, Sheridan Road, Clark Street, Ogden Avenue, Ashland Avenue, Halsted Street, Cermak Road, Michigan Avenue and Roosevelt Road and many more that aren't on the actual route will be affected. All of the closures will start about 7 a.m. today (though some roads in the Grant Park area are already closed) and the roads are expected to re-open gradually as the runners pass. Here's a detailed map of road closures.