Arunachal is the largest of all the Northeastern states in India.Total Area of Arunachal Pradesh is 83,743 square kilometer. Latitudinal and Longitudinal position of Arunachal Pradesh is between 26.28° N and 29.30° N latitude and 91.20° E and 97.30° respectively.
The land is mostly mountainous with the Himalayan ranges running north south. Relief of Arunchal Pradesh divides it into 5 river valleys:
- the Kameng,
- the Subansiri,
- the Brahmaputra or the Siang,
- the Lohit and
Fig: Arunachal Pradesh: Political Map
The entire above river are snow-fed. Most important of these is Brahmaputra (called Siang locally), which have Lohit and Subansiri as its tributaries.
Most of Arunachal Pradesh is covered by the Himalayas. However, parts ofLohit, Tirap and Changlang comes under Patkai bum hills which is art of Eastern Himalayas. Kangto, NyegiKangsang, the main Gorichenpeak, and the Eastern Gorichen peak are some of the highest peaks in this region of the Himalayas
The Himalayan ranges that extend up to the eastern Arunachal separate it from Tibet. The ranges extend toward Nagaland, and form a boundary between India and Burma in Changlang and Tirap district, acting as a natural barrier called Patkai Bum Hills. Mountains of Himalayas range comes under Shivalik rage. Therefore, their height is lower than the Greater Himalayas.
The Arunachal’s terrain is full of deep valleys alternating with highland plateaus and ridges. These features rise in the north adjacent to the peaks of the Himalayan range.
We can divide the topography in 3 categories:
- Northern Part
- Middle Part
- Lower Part
- Northern Part is the extension of Greater Himalayas. It forms boundary between India and Tibet. This part has very rough terrain and it is covered with snow most of the year. Kangto is the highest peak of this range with height of 7,060 meter.
- Middle part has somewhat lesser high mountain and it is very narrow stretch.
- Southern Part lies in the foothills of the Himalayas and is extension of Shivalik range of Himalayas, with height ranges from 1,000 to 3,300 feet
It can be seen that three broad features characterise thetopography of the region: Farthest south is a series of foothills, much like the Siwalik Range — a narrow sub-Himalayan belt stretching across much of northern India — that ascend from the Assam plains to elevations of 1,000-3,300 feet.
These hills rise rapidly northward to the lesser Himalayas, where some ridges and spurs reach 10,000 feet.