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 into Thailand, about upstream from the border. In October 2013 the cast and crew of the British television show "Top Gear" constructed a bridge over the river Kok as part of their Burma Special. The bridge was originally planned to be built over the River Kwai, but the River Fang which flows into the River Kok was chosen "accidentally". The show aired in two parts on 9 March 2014 and 16 March 2014. Kok River The Kok River (, , ) flows in Southeast Asia. The river originates in the Daen Lao Range, Shan State, Burma. It flows eastwards across