The James River (also known as the Jim River or the Dakota River) is a tributary of the Missouri River, approximately 710 mi (1,143 km) long, draining an area of 20,653 square miles (53,490 km²) in the U.S. states of North Dakota and South Dakota. About 70% of the drainage area is in South Dakota. The river provides the main drainage of the flat lowland area of the Dakotas between the two plateau regions known as the Coteau du Missouri and the Coteau des Prairies.