The Rock CF Thumb Coast Marathon

The Rock CF Thumb Coast Marathon, Half Marathon, and 5K take place on Michigan’s scenic Thumb Coast, starting November 2, 2025. The event features a flat, fast, fully paved, USATF-certified course with stunning views of Lake Huron. The full marathon is a point-to-point race from downtown Caseville to downtown Port Austin.

The half marathon begins at Sleeper State Park and finishes in Port Austin, while the 5K is a loop around downtown Port Austin, sharing the same finish line. Organized by the Rock CF Foundation and Trivium Racing, proceeds support cystic fibrosis research and care. Virtual race options are also available. Visit the organization's website for the most recent information.