Thumb Coast Marathon

The Thumb Coast Marathon is a point-to-point race along Lake Huron's Saginaw Bay shoreline in Michigan's Thumb region, starting in downtown Caseville and finishing on Main Street in Port Austin. The USATF-certified course is flat and fully paved, gaining about 265 feet over 26.2 miles and passing Point Crescent State Park near the finish. It is a Boston Qualifier: 8.9% of finishers in the 2025 inaugural race hit a BQ time, and the course carries a 99.45 course score, the second-fastest marathon course in Michigan. Race weekend also includes a half marathon starting at Sleeper State Park and a 5K in downtown Port Austin.