Flat Lake   Be the first to submit input for Flat Lake. If you have info on Flat Lake, Marshall County, South Dakota please submit it here to improve this web site.          These outdoors activities are available near Flat Lake.   Lakes Near Flat Lake: Pickerel Lake, Day County, 17 miles away Waubay Lake, Day County, 18 miles away Enemy Swim Lake, Day County, 20 miles away   Public Lands Near Flat Lake: Roy Lake State Park, South Dakota, 5 miles away Fort Sisseton State Park, South Dakota, 11 miles away Sica Hollow State Park, South Dakota, 12 miles away   Camp Grounds Near Flat Lake: Roy Kota Resort, Lake City, 5 miles away   Hotels Near Flat Lake: Super 8 Sisseton, Sisseton, 27 miles away Super 8 Lisbon, Lisbon, 36 miles away Dakota Magic Casino & Hotel, Hankinson, 42 miles away Best Western Ramkota Hotel, Watertown, 48 miles away Rodeway Inn Watertown, Watertown, 48 miles away