The forest steeped in deep legend and mystery. The word Sinharaja means lion (sinha) king (raja) and the popular belief is that the legendary origin of the Sinhala people in Sri Lanka is from the descendants of the union the lion king who once lived in the forest and a princess. Sinharaja Forest Reserve is one of the least disturbed and biologically unique lowland rain forests now remaining in Sri Lanka. This forest covers an extent of approximately 11187 ha. From east to west the length of the forest is about 21 km. And its width from north to south is about 3.7 km.

Sinharaja forest consists of a series of continuous ridges, aligned approximately in an east-west direction and lies between the tributaries of the Kalu Ganga in the north and the Gin Ganga in the south. There are four main routes of access to Sinharaja.

The Kalawana- Weddagala road from the northwest, The Rakwana-Morning side estate road from the northeast, the Hiniduma-Neluwa road from the southwest and Deniyaya-Pallegama road from the southeast. Among these roads, the Kalawana-Weddagala road is shorter and more convenient for visitors traveling from Colombo.

The untapped genetic potential of Sinharaja flora is enormous of the 211 woody trees and lianas so far identified within the reserve 139 (66%) are endemic. Out of 25 genera endemic to Sri Lanka 13 are represent in Sinharaja. The total vegetation density, including trees, shrubs, herbs, and seedlings has been estimated to be around 240,000 individuals per hectare, of which 95% comprise individuals of the ground layer below 1m in height.

Wildlife is not as easily seen as at dry-zone national parks such as Yala. There are about 3 elephants and 15 or leopards. The most common larger mammal is the endemic purple-faced langur. Birds tend to move in mixed feeding flocks, invariably led by the fearless Sri Lanka Crested Drongo and the noisy orange-billed babbler. Of Sri Lanka’s 26 endemic birds, the 20 rainforest species all occur here, including the elusive red-faced malkoha, Green-billed coucal, and Sri Lanka blue magpie. Reptiles include the endemic green pit viper and hump-nosed vipers, and there are a large variety of amphibians, especially tree frogs. Invertebrates include the endemic common birdwing butterfly and leeches.