Namdapha National Park is the largest protected area in the Eastern Himalaya biodiversity hotspot and is located in the state of Arunachal Pradesh. With an area of 1,985.23 square kms with 177 km2 in buffer zone and 1808 km2 in the core area. is the 3rd largest national park in India in terms of area. It is recognized as one of the richest areas in biodiversity in India. The park harbours the northernmost lowland evergreen rainforests in the world. The area is also known for extensive Dipterocarp forests, comprising the northwestern parts of the eco-region of Mizoram-Manipur-Kachin rain forests.
The park is located in Changlang district of Arunachal Pradesh, bordering with Myanmar. The park is located between the Dapha bum range of the Mishmi Hills and the Patkai range with a wide altitudinal range between 200 meters asl and 4571 meters asl. The habitat changes with increasing altitude from tropical moist forests to Montane forests, temperate forests and at the higher elevations, to Alpine meadows and perennial snow. The park has extensive bamboo forests and secondary forests in addition to the primary forests.
Because of many different vegetation zones, the park is home to a great diversity of mammal species. The Four big cat species are found in the park: snow leopards, clouded leopards, common leopards and tigers making it the only national park in the country. Other large predators are dholes, wolves, and Asiatic black bears. Smaller carnivores include red panda, red fox, yellow-throated marten, Eurasian otter, Oriental small-clawed otter, spotted linsang, binturong, common palm civet, small indian civet, large indian civet, masked palm civet, marbled cat, fishing cat, Asiatic golden cat, and two species of mongoose. Large herbivores are Asian elephants wild boar, forest musk deer, indian muntjac, hog deer, sambar, gaur, common goral, mainland serow, takin and bharal. Seven species of non-human primates including Stump-tailed macaque and Slow Loris, Hoolock Gibbons, Capped Langurs, Assamese Macaques and Rhesus Macaques.
The Avifauna of Namdapha national park has about 425 bird species with many more to be recorded from the higher areas. There are five species of hornbills recorded from the area. Several species of rare wren-babblers have been recorded in Namdapha. Other bird groups include laughing thrushes, parrotbills, fulvettas, shrike babblers and scimitar babblers. The snowy-throated babbler is a rare species of babbler found only in the Patkai and Mishmi hills and nearby areas in Northern Myanmar, is found in Namdapha. Other rare, restricted range or globally endangered species include the rufous-throated hill-partridge, and whitecheeked hill partridge. Ward's trogon, rufous-necked hornbill, green cochoa, Himalayan wood-owl, beautiful nuthatch, ruddy kingfisher, blue-eared kingfisher, white-tailed fish eagle, purple cochoa, Eurasian hobby, pied falconet, white-winged wood duck, Several leaf warblers and migrants such as amur falcon and several thrushes can be seen here. The first mid-winter waterfowl census in Namdapha was conducted in 1994 when species such as the white-bellied heron, a Critically Endangared bird was recorded for the first time.
The region is also very rich in Lepidoptera species. Both butterflies and moths are found in equal abundance here, along with a variety of other insects. These include the East Himalayan Purple Red Caliph, Emperor Koh-i-noor, Fluffy Tit, Naga Treebrown, Cruiser, Wizard etc.