Marine Mill, the first commercial sawmill in Minnesota, operated in Marine Mills (Marine on St. Croix) along the banks of the St. Croix River from 1839 to 1895. Over a period of about six decades, the mill produced millions of board feet of lumber and provided construction material used in towns and cities throughout the state. The remaining ruins were placed on the National Register of Historic Places in 1970 and opened to the public as a park and historic site two years later. The Marine on St. Croix Historic District, created in 1974, includes the mill’s remains.