The Red River (French: rivière Rouge) is a North American river. Originating at the confluence of the Bois de Sioux and Otter Tail rivers in the United States, it flows northward through the Red River Valley and forms the border between the U.S. states of Minnesota and North Dakota before continuing into Manitoba, Canada. It empties into Lake Winnipeg, whose waters join the world's oceans in Hudson Bay via the Nelson River.