Salween River much of its length, the Salween's course is nearly parallel to that of the much larger Mekong in the east. Although the commonly accepted name is Salween, the river is known by a handful of other names regionally: "Nu" in China, "Thanlwin" in southern Burma, and "Salawin" on the border of Thailand and Burma. Several major sub-continental drainage basins border on the Salween. The Mekong basin forms nearly the entire eastern boundary of the watershed, while the Irrawaddy River flows southwards on the west side of the basin. The smallest boundary is formed by the Yangtze to the extreme north.
Ruak River Province. The boundary section of the river is long. Ruak River The Ruak River (, , ; ) is a right hand tributary of the Mekong. The mouth of the Ruak river is at the Thai-Burma border opposite Laos, a spot known as the "Golden Triangle", a popular tourist destination. The Ruak originates within the hills of the Daen Lao Range, Shan State (Burma), and becomes the boundary river between Thailand and Burma at the confluence with the Mae Sai River near the northernmost point of Thailand. It then meanders eastwards until it empties into the Mekong River at Ban