Monson Lake State Park is a state park of Minnesota, USA, originally established as a memorial to 13 Swedish American pioneers who were killed there in the Dakota War of 1862. A district of 1930s New Deal structures is on the National Register of Historic Places. Despite being nearly doubled in size in 2009, the state park remains one of Minnesota's smallest. It is located off Minnesota State Highway 9 just west of Sunburg and northwest of Willmar. This seasonally-staffed park is managed from nearby Sibley State Park.