- The St. Croix Boom Site is a historic and scenic wayside on the St. Croix River in Stillwater Township, Minnesota, United States. It commemorates the location of a critical log boom where, from 1856 to 1914, timber from upriver was sorted and stored before being dispatched to sawmills downstream. The site was developed as a roadside park along Minnesota State Highway 95 in the 1930s. In 1966 it was designated a National Historic Landmark for its national significance in the theme of industry. It was nominated for being the earliest, most important, and longest serving of the log storage and handling operations that supported Minnesota’s major logging industry. Virtually no traces remain of the site’s original buildings and structures.