Flat Creek is a stream in Benton, Morgan andPettis counties in the U.S. state of Missouri. It is a tributary of the Lamine River. The stream headwaters arise in northern Benton County west of Ionia at 38°29′25″N 93°22′43″W / 38.49028°N 93.37861°W and the stream flows northwest past into Pettis County east of Windsor and then turns to the northeast passing under Missouri Route 52 south of Sedalia. The stream meanders to the east passing south of Smithton into Morgan County and under Missouri Route 135 to its confluence with Richland Creek to form the Lamine River at 38°40′07″N 92°57′11″W / 38.66861°N 92.95306°W.