Physical Geography: Manas is located in the foothills of the Eastern Himalaya and is densely forested. The Manas river flows through the west of the park and is the main river within it. It is a major tributary of Brahmaputra river and splits into two separate rivers, the Bwrsi and Bholkaduba as it reaches the plains. Five other smaller rivers also flow through the national park which lies on a wide, low-lying alluvial terrace spreading out below the foothills of the outer Himalaya. The Manas river also serves as an international border dividing India and Bhutan. The bedrock of the savanna area in the north of the park is made up of limestone and sandstone, whereas the grasslands in the south of the park stand on deep deposits of fine alluvium. The combination of Sub-Himalayan Bhabar Terai formation along with the riverine succession continuing up to Sub-Himalayan mountain forest makes it one of the richest areas of biodiversity in the world. The park is in the area and is situated at an altitude of above mean sea level.