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
Kok River Kok River The Kok River (, , ) flows in Southeast Asia. The river originates in the Daen Lao Range, Shan State, Burma. It flows eastwards across the Burma-Thailand border, coming in at the Thai border town of Tha Ton (, also spelled Thaton ). It flows to Mae Ai district, Chiang Mai Province. Most of its length in Thailand is in Chiang Rai Province where it passes Mueang Chiang Rai District after which it bends northeastwards and flows through Mae Chan, Wiang Chai and Chiang Saen districts. It is a wide, shallow, and slow-moving river. There is about of