The 1837 Treaty of St. Peters with the Ojibwe gave the United States government a large tract of land in what today is north central Wisconsin and east central Minnesota. This opened the region to logging. The river was important to float the logs downstream to the sawmills that processed it. During the 1840s, important sawmills were located at St. Croix Falls and Marine on St. Croix. In the 1850s Stillwater became the primary lumber destination. During this time the population of Stillwater grew rapidly. New sawmills were opened, and the town saw an influx of capital, primarily from lumber companies based in St. Louis. In 1856 construction began on a boom site two miles north of Stillwater. It was used to hold and sort the logs floating downstream. The boom was in operation for over fifty years. The St. Croix Boom Site is now a wayside rest and National Historic Landmark along Minnesota State Highway 95.