Valmiki Tiger Reserve forms the eastern most limit of the Himalayan Terai forests in India, and is the only tiger reserve of Bihar. Situated in the Gangetic Plains bio-geographic zone of the country, the forest has combination of bhabar and terai tracts. Valmiki Tiger Reserve lies in the north-westernmost West Champaran district of Bihar. Name of the district has been derived from two words Champa and Aranya meaning Forest of Champa trees.
Wild mammals found in the forests of Valmiki Tiger Reserve are Tiger, Sloth bear, Leopard, Wild dog, Bison, Wild boar etc. Several species of deer and antelopes viz barking deer, spotted deer, hog deer, sambar and blue bull are also found here. In Madanpur forest block large number of Indian flying foxes can be sighted. The Reserve has rich avi-fauna diversity. Over 250 species of birds have been reported.