Red River

River in north Vietnam, 500 km/310 mi long, that flows into the Gulf of Tonkin. Its extensive delta is a main centre of population.

Red River

Western tributary of the Mississippi River, USA, 1,638 km/1,018 mi long; so called because of the reddish soil sediment it carries. Formed in Oklahoma by the confluence of the North Fork and the Prairie Dog Town Fork, it flows through Texas, Arkansas, and Louisiana, before entering the Mississippi near Baton Rouge, about 500 km/310 mi above the Gulf of Mexico. The stretch that forms the Texas–Oklahoma border is called Tornado Alley because of the storms caused by the collision in spring of warm air from the Gulf of Mexico with cold fronts from the north. The largest city on its course is Shreveport, Louisiana.

Numerous lakes and bays, which contain an abundance of freshwater fish, occur in its lower reaches.

The Prairie Dog Town Fork rises in Staked Plains, Texas, and passes through Palo Duro canyon, 160 km/100 mi long and 300 m/984 ft deep.