Flat Lake   Be the first to submit input for Flat Lake. If you have info on Flat Lake, Sheridan County, Montana please submit it here to improve this web site.          These outdoors activities are available near Flat Lake.   Hotels Near Flat Lake: Candlewood Suites WILLISTON, Williston, 46 miles away Missouri Flats Inn, Williston, 46 miles away Marquis Plaza And Suites, Williston, 46 miles away Microtel Williston, Williston, 46 miles away