Red River (Asia) - Geography

Geography

The Red River begins in China's Yunnan province in the mountains south of Dali. It flows generally southeastward, passing through Dai ethnic minority areas before leaving China through Yunnan's Honghe Autonomous Prefecture. It enters Vietnam at Lào Cai Province. It forms a portion of the international border between China and Vietnam. The river, known as Thao River for this upper stretch, continues its southeasterly course through northwestern Vietnam before emerging from the mountains to reach the midlands. Its main tributaries, the Da River and Lo River join in to form the very broad Hong near Viet Tri. Downstream from Viet Tri, the river and its many distributaries spread out to form the Red River Delta. The Red River flows past the Vietnamese capital Hanoi before emptying into the Gulf of Tonkin.

Tonkin is the former name of the northern provinces of Vietnam and thus the eponymous body of water receiving the main river of "Tonkin".

The reddish-brown heavily silt-laden water gives the river its name. The Red River is notorious for its violent floods with its seasonally wide volume fluctuations. The delta is a major agricultural area of Vietnam with vast area devoted to rice. The land is protected by an elaborate network of dikes and levees.

The Black River and Lô River are the Red River's two chief tributaries.