The Chicago Lakefront 50K, 20.7M, and Half Marathon offers a rich history with multiple decades of tradition across races geared towards more seasoned runners. Chicago’s longest running ultra race features three, 10.3-mile out-and-back laps on the pedestrian path of the scenic Chicago Lakefront Trail. The Half Marathon follows the same course but with one “short” lap and one “long lap” The 20.7M follows the same course, but totaling two laps.