Assam, the eastern most state of the Indian sub-continent, extends
from 22o19' to 28o16' North Latitude and 89o42'
to 96o30' East Longitude between the foot hills of the
Eastern Himalayas and the Patkai and Naga Ranges. Assam is bordered
in the North and East by the Kingdom of Bhutan and Arunachal Pradesh.
Along the south lies Nagaland, Manipur and Mizoram. Meghalaya lies
to her South-West, Bengal and Bangladesh to her West. Assam
is connected with the rest of the Indian Union by a narrow corridor
in West Bengal that runs for 56km below the foothills of Bhutan
state is divided into three broad geographic units:
The lower and central Assam hills, known as
the Shillong Plateau
The Barail ranges and the low hilly terrains
of Mizo hills
The Alluvial valley of Brahmaputra, Dhansiri
and the Barak river
(I)The lower and central Assam range which includes,
from west to east, the Garo, Khasi, Jaintia and the outlying
Mikir hills are in reality a plateau or table-land. The general
height of the plateau ranges between 3,000ft and 6,000ft. The Khasi
and Jaintai hill portion of the plateau are comparatively higher
and flatter than the Garo and Mikir hills on the west and northeast.
The highest peak of the plateau is the Shillong peak (6450 ft).
(II) The lofty Barail ranges, also known as the
North Cachar hills, are separated from the Shillong plateau on the
Northwest by a system of narrow valleys. Tectonically, the Barails
form a south westerly extension of the mountain chain of Nagaland
and western Burma. It is this chain of mountain that separates the
valley of Irrawaddy and Chindwin of Burma from the valley of Brahmaputra
and the Meghna. The Patkai, Naga and Manipur hills and the Mizo
hills, form part of this great mountain system. The Mizo hills consist
of a belt of North-South trending ridges with intricate valleys,
with an average height of 3,000ft.
(III) The alluvial plains of Assam consist of two
a) the valley of the Brahmaputra and its tributaries
and b) the Barak valley.
These are separated from each other by the water
shed of the Shillong plateau and the Barail ranges.
The Brahmaputra valley separates the sub-Himalayan
foothills from the Shillong plateau and the Patkai-Naga hill ranges.
The Mizo hills and the Barail ranges die out towards the west and
south west into the plains of Cachar, which is a part of Surma-Kusiyara