Silent Valley National Park, established in 1984, lies about 40 km from Mannarkkad, Palakkad District of North Kerala and is spread over an area of 237.5 sq km. A unique preserve of tropical evergreen natural rainforests, only 90 sq km of the national park is accessible for tourists, allowing the wild to flourish in its natural surroundings the way it wants, in the rest of the area, known as the buffer zone. These rainforests are believed to date back 50 million years, according to botanists. Situated in the heart of the Nilgiri Biosphere Reserve, the forest strip of Silent Valley National Park brings summer rains to the state of Kerala. The altitude of the national park varies from 900 m to 2383 m, with the highest peak being Ankinda at 2383 m.
The biodiversity of the park is evident in the 1000 species of flowering plants, 107 orchids, 100 fern and fern allies, 200 liverworts, 75 lichens, and about 200 algae that flourish here. Around 30 species of mammals, 19 of amphibians, 200 of birds of which 15 are endemic to Western Ghats, 35 of reptiles, 225 of insects (survey in progress), and 128 species of butterflies have been reported to prosper in the national park. The park is also home to the endangered lion-tailed macaque. Besides these animals, there are numerous other species of wildlife like Malabar Giant Squirrel, black langurs, striped necked mongoose, fishing cat, Nilgiri langur, Indian wild boar, and several others.
The climate of the Silent Valley National Park is tropical with mild winters from December to January. The park receives comparatively high average annual rainfall of about 6000 mm. Both, the southwest and the northeast monsoons contribute to the rainfall with the chunk of it occurring during the months June through August. However, there is considerate variation in the amount of rainfall as you move from foothills to the higher altitudes. Like rainfall, the temperature also fluctuates according to the elevation. The average minimum temperature ranges from 8 0C to 14 0C while the average maximum temperature varies between 23 0C and 29 0C. However, the temperature in the plains is between 21 0C and 40 0C with the hilly areas ranging from 10 0C to 30 0C.
Regular nature camps are organized by the Kerala Forest and Wildlife Department for students and members of the environment related nongovernmental organizations. Accommodation facilities are available at the Inspection Bungalow in the base camp of the national park, Mukkali; reservation for which is done in advance. The nearest railhead is Palakkad Junction, about 60 km from the base camp of the national park in Mukkali and the closest airport is Cochin International Airport, 135 km from the national park. The best season to visit is from November to March.
The Silent valley National park in Kerala is located at the center of the Nilgiri Biosphere reserve.