Natural population Regions
In distribution of population, Arunachal Pradesh can be divided into
six natural regions. The first two regions are the Western parts
of Kameng District and Tirap District where there are comparatively large
concentration of population. The upper, the middle and the lower belts
of the remaining parts of Arunachal Pradesh constitute other three
distinct regions. The concentrated population pockets on the foot hills
constitute the sixth region.
The terrain mostly consists of submontane and mountainous
ranges with the Himalayan range along the northern borders criss- crossed
with ranges running north-south. The rivers have created broad valleys
in these areas. Due to the heavy rains,
the forests are luxuriant in growth
and large game inhabit them. Population is scanty.
The Brahmaputra, India's major river enters Arunachal
Pradesh from Tibet and flows into Assam from where it goes down
to Bangladesh before falling into the Bay of Bengal. The state gets
as much as five hundred centimeters of rain fall and this accounts for
the large number of rivers and lakes in the region apart from extensive
forests. The rivers Kameng, Subansiri, Siang, Lohit and Tirap have divided
the plains of Assam into valleys.