Northern Thailand - Geography

Geography

Parallel mountain ranges extend from the Daen Lao Range (ทิวเขาแดนลาว), in the southern region of the Shan Hills, in a north/south direction, the Dawna Range (ทิวเขาดอยมอนกุจู) forming the western border of Thailand between Mae Hong Son and the Salween River. To the east the Thanon Thong Chai Range (เทือกเขาถนนธงชัย), the Khun Tan Range (อยขุนตาน), the Phi Pan Nam Range (ทิวเขาผีปันน้ำ), as well as the western part of the Luang Prabang Range (ะทิวเขาหลวงพระบาง), form the natural region of the Thai Highlands together with the former.

These high mountains are incised by steep river valleys and upland areas that border the central plain. A series of rivers, including the Nan, Ping, Wang, Yom and Nan, flow southwards through mountain valleys and join to form the Chao Phraya in Nakhon Sawan Province in the central region. Sirikit Dam is situated on the Nan River in Uttaradit Province. The Northeastern part is drained by rivers flowing into the Mekong basin, like the Kok and Ing.

The four-region system includes the northern parts of the Central Plain as well as some mountainous areas bordering the western and the northeastern limits.