Pakke Tiger Reserve sits in the undulating foothills of the Eastern Himalayas, in Arunachal Pradesh's Pakke Kessang District. The Kameng River (also called the Bhareli) defines its western and northern edges, while the Pakke River marks the east. Between these waterways, the terrain rises from roughly 150 meters to the forested ridgelines above, creating a compressed gradient of habitats that supports extraordinary biodiversity. Contiguous forests surround the reserve on most sides: the 1,064-square-kilometer Papum Reserve Forest to the east, Nameri National Park in Assam to the south, and the Eaglenest Wildlife Sanctuary and Doimara Reserve Forest to the west. The perennial streams of the Nameri, Khari, and Upper Dikorai cut through the interior, feeding a landscape that receives 2,500 millimeters of annual rainfall, mostly during the southwest monsoon from May through September.

Walk through Pakke's lowland forests and the relationship between animals and trees becomes visible. Sixty-four percent of the reserve's tree species rely on animals to disperse their seeds, one of the highest proportions documented in any Indian forest. Great hornbills and wreathed hornbills are among the most important dispersers, carrying fruit over long distances and depositing seeds far from the parent tree. The forests themselves shift with elevation: tropical semi-evergreen stands of Mesua ferrea and Altingia excelsa cover the lower plains, giving way to subtropical broadleaved forests dominated by oak and laurel families on the higher ridges. Bamboo, cane, and the tokko palm (Livistona jenkinsiana, whose fronds locals use for thatching) crowd the moister stream gullies. Along the larger rivers, the tall red-flowered semal trees (Bombax ceiba) stand in isolation against beds of shingle and tall grass.

At least 40 mammal species inhabit the reserve, including tigers, leopards, clouded leopards, dholes, Himalayan black bears, Asian elephants, gaur, and the elusive binturong. The birding is exceptional even by Eastern Himalayan standards. Pakke hosts Jerdon's baza, the diminutive pied falconet, grey peacock-pheasants, red-headed trogons, and the spectacular great hornbill, whose wingbeats can be heard from hundreds of meters away. Blue-naped pittas call from the forest floor, sultan tits flash their yellow crests in the canopy, and ruby-cheeked sunbirds work the flowering understory. The reserve's location at the junction of the Indo-Malayan and Palearctic biogeographic zones gives it a species mix found in few other places on earth.

The reserve's protection model is built on community partnership rather than exclusion. Twenty-seven anti-poaching camps employ 104 local youth and 20 gaon buras (village elders) as forest watchers. But the deeper structure is the Ghora Aabhe Society, formed in 2006, which brings together twelve village chiefs who enforce customary laws against hunting and logging, levy fines for killing tigers, and coordinate with the forest department on conservation strategy. Women's Self Help Groups contribute intelligence and enforce local rules. The Hornbill Nest Adoption Programme, which earned the 2016 India Biodiversity Award, engages community members as nest guardians who monitor breeding pairs through the season. The Nyishi tribe's decision to replace real hornbill beaks with fiberglass replicas in their traditional headgear was a choice made by the community itself, not imposed from outside. A 41-kilometer road built through the reserve serves dual purpose: easing logistics for patrols while making the forest interior accessible enough that poachers cannot operate unseen.