Minneopa State Park is a state park in the U.S. state of Minnesota. It was established in 1905 to preserve Minneopa Falls, a large waterfall for southern Minnesota, and was expanded in the 1960s to include the lower reaches of Minneopa Creek and a large tract of prairie. Minneopa is Minnesota's third oldest state park, after Itasca and Interstate. Two park resources are listed on the National Register of Historic Places: the 1862 Seppman Mill and a district of seven Rustic Style structures built by the Works Progress Administration in the late 1930s. The park is located almost entirely on the south side of the Minnesota River, 3 miles (4.8 km) west of Mankato. In 2015 the state reintroduced American bison to the park in a 330-acre (130 ha) fenced enclosure, through which visitors can drive