The Himalayas bend sharply to the south beyond the Dihang gorge and move outwards to form a covering the eastern boundary of the country. They are known as ‘the Eastern or Purvanchal Hills’. It extended in the north-eastern states of India. Most of these hills are extended along the border of India and Myanmar while others are inside India namely- the Patkai Bum Hills, the Naga Hills and the Mizo Hills.
Major Hills of Purvanchal Hills
• Daffla Hills: It is situated to the north of the Tezpur and North Lakhimpur, and is bounded on the west by the Aka Hills and on the east by the Abor Range.
• Abor Hills: It is located in a region of Arunachal Pradesh in the far north-east of India, near the border with China. It is bordered by the Mishmi Hills and Miri Hills. This region is drained by the Dibang River, a tributary of the Brahmaputra.
• Mishmi Hills: These hills are located in the southward extension of the Great Himalayan ranges and its northern and eastern parts touches China.
• Patkai Bum Hills: It is situated India's North-Eastern border with Burma. The word "patkai" means "to cut chicken" in Tai-Ahom language. It is originated by the same tectonic processes that resulted in the formation of the Himalayas in the Mesozoic. These hills are crammed with conical peaks, steep slopes and deep valleys but they are not as rough as the Himalayas. The whole region is surrounded by forests comprising of sandstones.
• Naga Hills: It is located in India extending into Myanmar which forms a divide between India and Myanmar.
• Manipur Hills: It is located in the north of Nagaland, Mizoram in the south, upper Myanmar in the east and Assam in the west bound Manipur Hills.
• Mizo Hills: It is formerly called Lushai Hills. It is located to in south-eastern Mizoram state, north-eastern India, forming part of the north Arakan Yoma system.
• Tripura Hills: These hills are a series of parallel north-south folds, decreasing in elevation to the south until they merge into the greater Ganges-Brahmaputra lowlands (also called the Eastern Plains). Each successive ridge of hills to the east rises higher than the one before; the low Deotamura Range is followed by the Artharamura, Langtarai, and Sakhan Tlang ranges.
• Mikir Hills: It is located to the south of the Kaziranga National Park. It is part of the Karbi Anglong Plateau. Radial drainage pattern is the best characteristic of this region where Dhansiri and Jamuna being the main rivers.
• Garo Hills: It is located in Meghalaya state and part of Garo-Khasi range which is consider as one of ‘the wettest places on earth’. Nokrek Peak is the highest peak of this region.
• Khasi Hills: It is a part of Garo-Khasi Range in the Meghalaya and got its name khasi tribes which are found in this region. Cherrapunji is situated in the East Khasi Hills and Lum Shyllong is the highest peak near to Shillong.
• Jaintia Hills: It is located further to the east from the Khasi Hills.