The Dudhwa National Park is a national park in the Terai belt of marshy grasslands of northern Uttar Pradesh, India. It stretches over an area of 490.3 km2, with a buffer zone of 190 km2. It is part of the Dudhwa Tiger Reserve in the Kheri and Lakhimpur districts. It is located on the Indo-Nepal border in the Lakhimpur Kheri District and has buffers of reserved forest areas on the northern and southern sides. It represents one of the few remaining areas of the diverse and productive Terai ecosystem, supporting many endangered species, obligate species of tall wet grasslands, and species of restricted distribution.
Dudhwa became a tiger reserve in 1979. The area was established in 1958 as a wildlife sanctuary for swamp deer. Thanks to the efforts of Billy Arjan Singh the area was notified as a national park in January 1977. In 1987, the park was declared a tiger reserve and brought under the purview of the ‘Project Tiger. Together with the Kishanpur Wildlife Sanctuary and the Katarniaghat Wildlife Sanctuary, it forms the Dudhwa Tiger Reserve.