A repository of rare and endangered flora and fauna, the valley is a major watershed for two important rivers-the Periyar and the Pamba. The famous Sabarimala shrine and the Mangala Devi Temple are also situated in the region.At the centre of the reserve is the vast artificial lake created by a dam built by the British in 1895. It was declared as a sanctuary in 1950.

Periyar Reserve became part of Project Tiger, a Central Government initiative to protect the animal.A combination of tropical, deciduous and evergreen forests and grasslands make this an ideal home for 62 species of mammals, 320 species of birds, and 45 species of reptiles. There are numerous varieties of flowers and butterflies as well. A boat ride on the lake is a delightful way of spotting elephants and avifauna, for which the park is well known. If you are fortunate, you might even spot the pride of the sanctuary, the tiger. Although tiger sightings are not very common, there are enough of these magnificent felines around. Trackers routinely spot pugmarks.

Spread over the Thodupuzha and Udumbanchola taluks, it includes a 33-sq-km scenic lake formed by the three dams-Cheruthoni, Idukki and Kulamavu. A charming canopy of dense tropical evergreen forests, tropical semi-evergreen forests and moist deciduous forests fringe the lake that surrounds this protected area on three sides.

Wildlife found here include herds of elephants, tiger, barking deer, bear, wild boar, sambar, wild dogs, jungle cats, and a large concentration of various species of snakes,including cobra,viper,python, krait, and numerous non-poisonous ones.The sanctuary is home to a variety of bird species and the extensive reservoir here attracts a lot of aquatic birds, such as ducks and cormorants. Small groups of tribals, the Adivasis, dwell in the higher areas of the sanctuary. Visitors are taken around in boats. The best time to visit is from November to March.