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
Passaic River flow south, through Morristown National Historical Park, and forms the boundary between Morris and Somerset counties. In its current path, it passes through the southeast edge and drains Lord Stirling Park then along the western edge of the Great Swamp, which it drains through several small tributaries including Black Brook. The river passes through a gorge in Millington and then turns abruptly northeast, flowing through the valley between Long Hill to the west and the Second Watchung Mountain to the east. It forms the boundary between Morris and Union counties as it passes Berkeley Heights, New Providence, and Summit. Near