The Ice Age Trail is a 1,200-mile National Scenic Trail across Wisconsin that follows the edge of the last glacier to shape the state, linking parks, forests, natural areas, and private land from Interstate State Park on the St. Croix River to Potawatomi State Park on Door Peninsula. Its route highlights glacial features such as kettles, eskers, kames, potholes, and erratics, and includes a side trail to Timms Hill, Wisconsin’s highest point. Inspired by Ray Zillmer, advanced by Henry S. Reuss, and established by Congress in 1980, it became part of the National Park System in 2023 and remains an evolving, heavily used hiking trail.