Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Big Muddy Creek is a tributary of the Missouri River, approximately 191 mi (307 km) long, in the Canadian province of Saskatchewan and the U.S. state of Montana. It flows through the Big Muddy Badlands. It rises in southern Saskatchewan, on the plains north of the international border and approximately 20 mi (32 km) northwest of Big Beaver. It flows southwest through the Big Muddy Badlands and through Big Muddy Lake, then south into Sheridan County, Montana, past Redstone, then east, pass Plentywood, then south, forming the eastern border of Fort Peck Indian Reservation. It joins the Missouri west of Culbertson.