A survey has recorded 165 butterfly species, 37 of them endangered, in Dehing Patkai National Park, Assam. The park spreads over 234.26 sq km in Dibrugarh and Tinsukia districts and is one of the surviving stretches of Assam Valley Tropical Wet Evergreen Forests. It forms the core of the 937 sq km Dehing Patkai Elephant Reserve.