The silent valley, spread over the area of 237.52 square kilometre is a well preserved natural wild life sanctuary and rainforests. It is having some of the distinctive extinct species of the world. It rises to the Nilgiri Plateau in the North extents to the plains of Mannarkkad in the South. It has a collection of Western Ghats biodiversity with more than 1000 species of flowering plants which include about 110 species of orchids, more than 34 species of mammals, about 200 species of butterflies, 400 species of moths, 128 species of beetles of which 10 are new to science, about 150 species of birds including almost all the 16 endemic birds of southern India.
The River Kunthi descends from the Nilgiri hills, from an altitude of 2000 m above sea level, and traverses the entire length of the valley and rushes down to the plains through the deep forest. The River Kunthi never turns brown and is always crystal clear, perennial and wild.