Katarniaghat Wildlife Sanctuary is a part of the Dudhwa Tiger Reserve, and is located in Uttar Pradesh near the India-Nepal border, in the Terai area of Bahraich district. It covers an area of 400 km2 (150 sq mi) and was established in 1976. The sanctuary is now being managed along with the Dudhwa National Park and Kishanpur Wildlife Sanctuary, as part of the Dudhwa Tiger Reserve under Project Tiger of the Government of India.
The Katerniaghat Forests provide strategic connectivity between tiger habitats of Dudhwa and Kishanpur in India and the Bardia National Park in Nepal. Its fragile Terai ecosystem comprises a mesmerizing mosaic of Sal and Teak forests, lush grasslands, steaming swamps and wetlands. it is unique for the number of endangered and critically endangered species, which occur here and include the gharial, tiger, rhino, Gangetic dolphin, Swamp Deer, Hispid hare, Bengal florican, the White-backed and Long-billed vultures.
One of the best places in the world for seeing the Gharial in its natural habitat is the Girwa River, where it is found sympatric with the mugger. This population was one of three that were still breeding, when the project to conserve this reptile from the verge of extinction was initiated in 1975. In the Girwa, mugger crocodiles are also seen though in much smaller numbers, as their favorite haunts are stagnant wetlands like the many taals andbaghars that occur in the sanctuary. Side by side the serenely swimming gharial can be seen frolicking Ganges dolphins.
The herpetofauna of Katerniaghat is highly fascinating and represented by several species such as the Banded Krait, the Burmese Rock Python, the Yellow Speckled Wolf-snake and the Paradise Flying Snake that have been discovered here fairly recently along with a number of other species still waiting to be discovered.