The Rock CF Thumb Coast Marathon

The Rock CF Thumb Coast Marathon, Half Marathon, and 5K is a scenic running event held on Michigan’s Thumb Coast, featuring a flat, fast, and fully paved USATF-certified course with stunning views of Lake Huron. Scheduled for November 2, 2025, the point-to-point marathon starts in historic downtown Caseville and finishes in downtown Port Austin. The half marathon begins at Sleeper State Park and also 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.