Silent Valley National Park is a beautiful representation of the last remaining rain forest of Kerala. Historically it’s a paradigm of people’s movement to protect the forest. Silent Valley was declared as National Park in 1984 and formally inaugurated in the year 1985. Initially there was only 89.52 sq.km. area under the Division which forms the core zone of the National Park. In 2007, an area of 148 sq.km. was added to this Division as buffer zone. In 1914, Silent Valley forests were declared as Reserved Forest. Till 1921, Silent Valley was part of South Malabar Forest Division with headquarters at Nilambur. During 1921, it came under control of Palakkad Forest Division and managed so until 1988.

The Western Ghats boasts one of the richest and unexplored landscapes in the world. The forests of the Silent Valley National Park harbour some of the most pristine, unique and highly productive forests in the world. In biogeographical sense Silent Valley and adjoining forests represent ‘Ecological islands’ in which conditions that prevailed before anthopogenic activities still exists. Exceptional species diversity and endemic value of Evergreen and Semi Evergreen communities is seen here. 41 mammals, 211 birds, 49 reptiles, 47 amphibians, 12 fishes, 164 butterflies and 400 species of moths are found here. Apart from this the park harbors a viable population of Lion tailed macaques which also is the flagship species of the Park. The indigenous tribal groups that live within park boundaries include Irulas, Kurumbas, Mudugas and Kattunaikkars, the ethnic heritage of these communities is well protected.

Silent Valley is located in the South-western corner of Nilgiris. The whole Park is a roughly rectangular tableland closed on all sides. It has high and continuous ridges along its entire east, north and northeast borders and a somewhat lower ridge along the entire western and southern border. Along its entire length, the plateau slopes toward the bed of Kunthipuzha, which divides it to two halves. The terrain is generally undulating with steep escarpments and many hillocks. The elevation ranges from 900 M to 2,300 M above MSL with the highest peak at 2,383 M (Anginda peak).

The terrain is generally undulating with steep escarpments and many hillocks. The elevation ranges from 900 M to 2,300 M above MSL with the highest peak at 2,383 M (Anginda peak). The area lies entirely on a plateau to the north of Mannarkkad, the outer slopes of the hills forming the tableland. The main basin of the Kunthipuzha, which runs from north to south and empties its waters into the Bharathapuzha, is covered by these forests.

A perennial river named Kunthipuzha is passing through the western side of the park, from north to south direction finally merging in to Bharathapuzha. Main tributaries of this river are Kunthancholapuzha, Karingathodu, Madrimaranthode, Valiaparathodu and Kummathanthode. All major tributaries of Kunthipuzha originate on the upper slopes of the eastern side of the Valley. The streams from the western slopes are dry in summer. The Bhavani River is a tributary of the Cauvery, one of the largest rivers in India. The river originates in Nilgiris, draining the south slope of the Nilgiri Hills. After flowing for a few kilometers southward it enters Kerala through a deep gorge and continues south for another 20 km, between two high, forested ridges till Mukkali. At Mukkali, Bhavani takes an abrupt 120° turn towards the northeast and flows for another 25 km through Attappady plateau and for 7 km. along the inter-State border.