Nestling at the foothills of the Himalayas, Assam is known as the land of Blue Hills and red rivers. The State has got a resource of fertile valleys, dense forests, numerous rivers, lofty hills and lovely undulating plains. The mighty river the Brahmaputra, which is also one of the four largest rivers of the world, along with its tributaries, is nourishing it from time immemorial. The long range of hills from East to the west have divided her into two major valleys called Brahmaputra and Barak or Surama valley. In between these valleys lie the Barail mountain range Rengma and Karbi hills with full of dense forest and rare species of wildlife.
The Brahmaputra Valley in Assam is approximately 80 to 100 km wide and almost 1000 km long. The width of the river itself is 16 km at many places within the valley. Most parts of the state are plains, except for Karbi Anglong, North Cachar and some parts of Guwahati which are hilly regions.