The Red River is a major river in the Southern United States. It was named for its reddish water color from passing through red-bed country in its watershed. It also is known as the Red River of the South to distinguish it from the Red River of the North, which flows between Minnesota and North Dakota into the Canadian province of Manitoba. Although once a tributary of the Mississippi River, the Red River now is a tributary of the Atchafalaya River, a distributary of the Mississippi that flows separately into the Gulf of Mexico. This confluence is connected to the Mississippi River by the Old River Control Structure.
The south bank of the Red River formed part of the US–Mexico border from the Adams–Onís Treaty (in force only in 1821) until the Texas Annexation and the Treaty of Guadalupe Hidalgo.
The Red River basin is the second-largest in the southern Great Plains. It rises in two branches in the Texas panhandle and flows eastward, serving as a border between the states of Texas and Oklahoma. It forms a short border between Texas and Arkansas before entering Arkansas. It forms much of the eastern border of Miller County, Arkansas, turning south near Fulton and flowing into Louisiana, where it feeds the Atchafalaya River. The total length of the river is 1,360 miles (2,190 km), with a mean flow of over 57,000 cubic feet per second (1,600 m3/s) at the mouth.



Quelle: Wikipedia