Silent Valley National Park (Core zone: 236.74 square kilometres (91 sq mi)) is located in the Nilgiri Hills, Palakkad District in Kerala, South India. The area in this national park was historically explored in 1847 by the botanist Robert Wight and is associated with Hindu legend.The Silent Valley is the largest national park in Kerala.

 

The park is one of the last undisturbed tracts of South Western Ghats mountain rain forests and tropical moist evergreen forest in India. Contiguous with the proposed Karimpuzha National Park (225 km²) to the north and Mukurthi National Park (78.46 km²) to the north-east, it is the core of the Nilgiri International Biosphere Reserve (1,455.4 km²), and is part of The Nilgiri Sub-Cluster (6,000+ km²), Western Ghats World Heritage Site, recognised by UNESCO