The Flat River is a stream in St. Francois County, Missouri.
[1] It is a tributary of the Big River.
The stream source is at: 37°46′14″N 90°35′20″W / 37.77056°N 90.58889°W / 37.77056; -90.58889 and the confluence is at: 37°53′31″N 90°29′59″W / 37.89194°N 90.49972°W / 37.89194; -90.49972.
[2] A variant name was "River la Platte".
This article related to a river in Missouri is a stub.