Dudhwa Tiger Reserve lies on the India-Nepal border in the foothills of the Himalaya and the plains of the ‘terai’ in Uttar Pradesh. From mosaic grasslands and dense sal forests to swampy marshes, the terrain of Dudhwa National Park is as diverse as the wildlife population it harbors. While the northern edge of the Park lies along the Indo-Nepal border, the River Suheli marks the southern boundary.A Tiger Reserve since 1879, Dudhwa became a National Park in 1977 and adopted the Project Tiger in 1988. Although the Tigers at the Park are numerous, sightings are rare due to the thick forest cover of the area. Besides Tigers, Leopards, Hispid Hares, Swamp Deer (Barasingha) and Rhinos thrive amidst the vegetation.Dudhwa is the last remnant of Terai region, one of the most endangered ecosystems on the planet.This complex ecosystem is a beautiful mosaic of dense Sal jungles, Grasslands and Swamps.
Forty-seven species of mammals are found at Dudhwa; of these thirteen species are endangered. Dudhwa is home to a sizable tiger population.A Tiger Reserve since 1879, Dudhwa became a National Park in 1977 and adopted the Project Tiger in 1988. 
Although the Tigers at the Park are numerous, sightings are rare due to the thick forest cover of the area. The other animals to be seen here include Swamp Deer, Sambar Deer, Tiger, Rhinoceros, Sloth Bear, Ratel, Barking Deer, Jackal, Jungle Cat, Leopard Cat, Spotted Deer, Hog Deer, Civet, Fishing Cat and many more. This place is the last refuge for critically endangered sub-species of the Swamp deer, Cervus duvauceli duvauceli (called Barasingha in Hindi).Out of the seven species of deer in India, five (swamp deer, sambar, barking deer, spotted deer and the hog deer) thrive at Dudhwa. The only place in the world inhabited by 5 species of deer.Dudwa National Park is a stronghold of the barasingha, swamp deer, which can be spotted in herds of hundreds, this species of deer is found only in India.
It is interesting to note that around half of the total Barasinghas on the Earth are present in Dudhwa National Park. Smaller than the sambar, the barasinghas have 12 antlers that collectively measure up to 100 cm.
Critically Endangered species like the Bengal Florican and Hispid Hare have been rediscovered at Dudhwa.Besides 13 species of mammals, 9 species of birds and 11 species of reptiles & amphibians are Endangered (listed in Schedule-1 of the Wildlife (Protection) Act). It includes among others, painted storks, black and white necked storks, Saras-Cranes, woodpeckers, barbets, kingfishers, minivans, bee-eaters, bulbuls and varied night birds of prey.Much of the park’s avian fauna is aquatic in nature, and is found around Dudhwa’s lakes- especially Banke Tal. The grasslands are the natural habitat of Indian one-horned Rhinoceros. About a hundred and fifty years ago the last rhino was hunted to extinction. Conservationists felt that Dudhwa could support a rhino population.
In 1984, rhinos from Assam and Nepal were introduced. The rhinos are kept inside an electrical fence and their activities are strictly monitored. The family has increased to 17, despite the initial hiccups.The Park affects the water and climatic conditions of the region. This is absolutely essential for the human survival and agriculture (the main thrust of local economy).
The major vegetation types in this region are tropical semi-evergreen forest, tropical moist deciduous forest, riparian and swamp forest and dry deciduous forest.
The various types of forests throughout the park are interrupted by wide stretches of mesophyllous grasslands locally called the phantas.