Runners follow a counter-clockwise loop route largely along the shoreline of Michigan’s Gross Ile at the Rock CF Rivers Half Marathon, whose proceeds go to benefit cystic fibrosis research. From the starting line at Grosse Ile Middle School, runners follow the loop route mostly around the edges of the island, along East River and West River roads, before crossing the finish line on the running track at Grosse Ile High School.
Note: The course map above provides the approximate route for the race. Though every effort has been made to ensure its accuracy, changes are sometimes made to race routes due to weather conditions, road closures or other circumstances that can require a course to be changed. If you see an error above, email us here.