Silent Valley is a virgin forest in the core area of Nilgiri Biosphere in Kundali hills of Western Ghats of south India. It spreads over an area of 9000 hectares. About 20 % is grass land
and the rest is a dense, cool and humid rain forest.The forest is known to be the home of several
species of plants and animals such as flowering plants like orchids, lichens, mosses, mammals, birds, amphibians and fishes. Acoording to the latest Zoological Survey, Out of the 315 species of animals recorded here, 28 species are new reports.
Silent Valley is surrounded with Attappadi Reserve Forests in
the east, and the reserved forests of the Palghat and Nilambur divisions in the west and the south. In the North, the park is an extension of the Nilgiri Forests.
The name for the forest in the local laguage is Sairandhrivanam (which means 'the forest in the valley'). In 1888 the region was declared a reserved land under the Forest Act and later was notified as a Reserved Forest by the Government of Madras in 1914.
In the 1970s the proposals were laid out by the government of Kerala for the construction of a hydro-electric plant in Silent Valley, which would cause mass destruction to valuable wild life resources. Protests were started by environmentalists all over the state, and the movement was led by Kerala Shasthra Sahitya Parishad. Associated studies led to the discovery of Nine new plant species and a new animal species in the forests of Silent Valley. This reinforced the spirit of the activists and the plans for the construction of the hydro-electric plant were temporarily abandoned. on 1984 November
15, the valley was declared as a totally protected National Park.