The Siwalik Hills are the outer most ranges or foot hills located to the south of the main Himalayas. They are the lowest range of the Himalayas, with a height of 600 to 1500mts and width varying from 15- 150 km. They extend from Jammu and Kashmir in the west to Arunachal Pradesh in the east. They have flat-bottom, structured valleys, which are known as ‘Doons’. eg: Dehradoon.
The Himalayas act as natural frontiers and prevent foreign invasion, they prevent the cold winds from central Asia. They obstruct the rain bearing winds and this causes heavy rainfall. They are a store house of minerals and the birthplace of many rivers and water falls.
