River systems of Thailand divides into two major branches, the " Tiền Giang" (Front River) and "Hậu Giang" (Back River). These in turn enter the South China Sea through nine estuaries. The following are the principal tributaries of Mekong River which flow through Thailand (tributaries entirely outside the Thai border not shown). The Mekong drains a considerable portion of northeast Thailand. In terms of Thai territory drained, it is second only to the Chao Phraya system. The Salawin River rises in Tibet (Tibetan: རྒྱལ་མོ་རྔུལ་ཆུ།) after which it flows through Yunnan, where it is known as the "Nujiang" River (), although either name can be
River systems of Thailand flow into the Mekong. The Mekong is the only river system in Thailand which drains into the South China Sea. The Chao Phraya River system is the main river system of Thailand, as its basin defines much of the region of central Thailand. The Chao Phraya River begins at the confluence of the Ping and Nan Rivers at Nakhon Sawan (also called Pak Nam Pho) in Nakhon Sawan Province. It then flows from north to south for from the central plains through Bangkok to the Gulf of Thailand. In Chai Nat, the river splits into the main river course and