The Red River (, American English: Red River of the North) is a North American river. Originating at the confluence of the Bois de Sioux and Otter Tail rivers between the U.S. states of Minnesota and North Dakota, it flows northward through the Red River Valley, forming the border of Minnesota and North Dakota and continuing into Manitoba, Canada. It empties into Lake Winnipeg, whose waters join the Nelson River and ultimately flow into the Hudson Bay.