The Parambikulam Wildlife Sanctuary is a reservoir of tranquil greenery ensconced in a valley between the Annamalai ranges of Tamil Nadu and the Nelliampathy ranges of Kerala. The areas hilly and rocky, drained by several rivers, including the Parambikulam, the Sholayar and the Thekkedy. Thickly forested with stands of bamboo, sandalwood, rosewood and teak, the sanctuary has some marshy land and scattered patches of grassland. Parambikulam was once home to some of south India's finest stands of teak. Little remains of the original teak forests, other than the famous Kannimari teak tree, the largest in Asia as most of these have now been replaced by teak plantations. The tree is about 5 km from Thunakadavu, and is one of Parambikulam's prime attractions. There are two watchtowers one at Anappadi, 8km from Thunakadavu, and other at Zungam, 5km from Thunakadavu.

Parambikulam has one of the largest population of gaur (bison). It is also a home to elephants, sloth bears, wild boars, sambhars, chital tigers, panthers and crocodiles. There are also bonnet macaques, spectacled cobras, kraits, vipers, turtles, darters, little cormorants and black eagles.

Parambikulam is open throughout the year, but is best avoided during the monsoon. Between June and August, the monsoon rains lash, making hillsides unstable and causing slush, mosquitoes, drippy roofs and other nuisances. Boat cruises can be arranged in the Parambikulam Reservoir. The rest house of the state forest department at Thoonakkadavu, Thellikkal and Elathode offer comfortable lodging facilities. A tree - house in the reserved forest area in Thoonakkadavu has to be booked in advance.