The Red River is the most southern of the large tributaries of the Mississippi River, extending 1290 miles. It is generally referred to as Red River from the point where Prairie Dog Town Fork emerges from the Texas Panhandle to join Oklahoma–Texas border. The main river is approximately 800 miles long. It rises in two branches in the Texas Panhandle and flows southeast between Texas and Oklahoma and between Texas and Arkansas to Fulton, Arkansas. It then turns south, enters Louisiana, and crosses southeast to the Atchafalaya and the Mississippi rivers. In Texas, it flows rapidly through a canyon in the semiarid plains, but later in its course, it spreads water into rich red-clay farm lands (from the name Red comes). Dams on the river include the Denison Dam (completed 1943), which impounds Lake Texoma, one of the largest reservoirs in the United States. The river is now navigable for small ships to maneuver above Natchitoches, Louisiana.
