It is one of the largest and least spoiled wilderness areas in the Terai, covering an area of 968 sq. km. The park is densely forested by Sal trees and carpeted with grass, savannah and reverine vegetation. The park has been home for endangered species like the rhinoceros, wild elephant, tiger, swamp deer, black buck, glacial, crocodile and Gangetic dolphin Endangered birds include the Bengal Florican, lesser florican, silver- eared mesia and sarus crane.