Explanation: The core of the Nilgiri Biosphere Reserve, the Silent Valley National Park is probably one of the most magnificent gifts of nature to mankind, a unique preserve of tropical rain forests in all its pristine glory with an almost unbroken ecological history.

• Silent Valley is closed on all sides with high and continuous ridges and steep escarpments, as a result the valley is shielded from the extremes of climate as well as anthropogenic interventions and so it remained an ecological island with a special micro climate.
• The river Kunthi descends from the Nilgiri Hills above an altitude of 2000 m and traverses the entire length of the valley finally rushing down to the plains through a deep gorge.
• Silent Valley falls within the revenue districts of Palakkad and Malappuram within the 76º 24’ and 76º 29’ East Longitude and 11º 4’ and 11º 13’ North Latitude.

Source: https://forest.kerala.gov.in/index.php/about-us/wildlife/2015-03-16-09-50-24/national-parks/silent-valley-national-park