Kanneliya, Dediyagala and Nakiyadeniya also known as KDN together form a tropical lowland rain forest complex making it the last large remaining rain forest after the famous Sinharaja Rain Forest. KDN situated in south of Sri Lanka has been identified as one of the places with the finest distribution of plants in the whole of South Asia. It was designated as a biosphere reserve in 2004 by UNESCO.
The Forest complex covers a total area of 5305 ha with the Kanneliya Rain Forest by itself having a land extent of 5108 ha. The Kanneliya National Park (KDN) made up of dense, less dense and plantation forests are a biodiversity hotspot with its wet evergreen vegetation that is home to many species of endemic wildlife. Furthermore KDN is an important catchment area for two important rivers and many streams that flow through the southern province. The forest reserve is home to close to 17 percent of lowland endemic floral species and 86 species of mammals, 20 endemic species of birds, 36 species of snakes, 23 species of lizards, 14 species of lizards, 32 species of butterflies and 20 percentage of the country’s endemic fish which inhabit the two main rivers that are fed by the springs of the Kanneliya Rain Forest. Some of the endemic birds found here include the endangered Red Faced Malkoha, Orange Billed babbler, Sri Lanka Blue Magpie, Sri Lanka Spurfowl and the Sri Lanka Jungle Fowl.