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
Hudson River lake. It next goes through Hudson Falls. At this point the river forms the boundary between Washington and Saratoga Counties. Here the river has an elevation of . Just south in Fort Edward, the river reaches its confluence with the Champlain Canal, which historically provided boat traffic between New York City and Montreal and the rest of Eastern Canada via the Hudson, Lake Champlain and the Saint Lawrence Seaway. Further south the Hudson takes in water from the Batten Kill River and Fish Creek near Schuylerville. The river then forms the boundary between Saratoga and Rensselaer counties. The river then