The hilly regions of the north-eastern and south-eastern part of Bangladesh have originated during the elevation of the Himalayans in Tertiary period They are similar to Lusai of Asam and Arakan hills of Mayanmar. These hills are situated in greater Sylhet, Chittagong, and the Chittagong Hill Tracts.
- Hills of Sylhet: In Moulavibazar, Habiganj and north-eastern part of Sylhet there are hills or hillock covered with grassland and trees. Usually, these are situated at 30 -60 meter (100 -200 feet) above sea level. In these hills tea cultivated. The highest hill of Sylhet region is the Patharia Hill. Its height is 240 meters (800 feet).
- Hills of Chittagong: In the northern region of Chittagong there are some small hills situated parallal with the seashore and are extended north to south The hills of Sitakunda and Chandranath are one of them. The highest peak here is 350 meters (1155 feet). In the south there are some small hilly range in between Cox’s Bazar and Teknaf.
- Hills of Chittagong Hill Tracts: There are many hills in the hilly district of Rangamati, Bandarban and Khagrachhari. These hills are extended from north to south. Normal height of these hills is not more than 600 meters (200 feet). Among the hills of Chittagong Hill Tracts, the highest one is Tajingdong (Bijoy), which is 1231 meters (4039 feet) in height. Other high hills are: Moudok Muyal -about 1000 meters (3292 feet), Reng Tiyang -about 920 meters (3141 feet), and Pyramid hill -about 920 meters (3016 feet).