The Knife River is a tributary of the Missouri River, approximately 120 mi (193 km) long, in North Dakota in the United States.Knife is an English translation of the Native American name.It rises in west central North Dakota, in the Killdeer Mountains in Billings County. It flows east, and is joined by Spring Creek near Beulah. It joins the Missouri north of Stanton, at the Knife River Indian Villages National Historic Site. Much of the terrain surrounding the river valley still remains in native grasslands, supporting many species of wildlife, including Whitetail Deer, Mule Deer, Coyote, Fox, Native Grouse, Pheasant, ... Source: Wikipedia