Sai River ( th, แม่สาย or แม่น้ำสาย; ; ), formerly known as the River of Lawa ( th, แม่ละว้า; ), is a river that forms the natural

border Borders are usually defined as geographical boundaries, imposed either by features such as oceans and terrain, or by political entities such as governments, sovereign states, federated states, and other subnational entities. Political borders c ...

between

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

and

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

Tachileik Tachileik (also spelt Tachilek; my, တာချီလိတ်, ; shn, တႃႈၶီႈလဵၵ်း, ; th, ท่าขี้เหล็ก, , ), is a border town in the Shan State of eastern Myanmar. It is the administrative seat of Ta ...

and Mae Sai Districts. Mae Sai town, where the bridge crossing the international border is located, is named after this river. It is a tributary of the

Ruak River The Ruak River ( th, แม่น้ำรวก, , ; nod, ) 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. Co ...

, itself a tributary of the

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annual ...

Course

The river has its sources in the

Daen Lao Range The Daen Lao Range ( th, ทิวเขาแดนลาว,
; my, Loi La) is a mountain range of t ...

, in

Shan State Shan State ( my, ရှမ်းပြည်နယ်, ; shn, မိူင်းတႆး, italics=no) also known by the endonyms Shanland, Muang Tai, and Tailong, is a state of Myanmar. Shan State borders China (Yunnan) to the north, Laos ( ...

. Then it flows southeastwards, bending eastwards at the feet of the northern end of the

Doi Nang Non Doi Nang Non ( th, ดอยนางนอน, ; 'Mountain of the Sleeping Lady') is a mountain range in the Thai highlands in Chiang Rai Province, Thailand. It is a karstic formation with numerous waterfalls and caves rising at the southern ...

ridge before flowing through the

/ Mae Sai urban area, where there is a sign marking the northernmost point of Thailand just east of the border-crossing bridge —at the meeting point of Thailand Route 1 and National Highway 4 (Burma)— over the river. Finally it flows northeastwards before joining the right side of the

, a tributary of the

, less than southeast of Tachileik Airport.

GoogleEarth Google Earth is a computer program that renders a 3D computer graphics, 3D representation of Earth based primarily on satellite imagery. The program maps the Earth by superimposition, superimposing satellite images, aerial photography, and geog ...

References

Myanmar–Thailand border Rivers of Myanmar Rivers of Thailand International rivers of Asia {{Myanmar-river-stub