The Barun Valley, the easternmost valley of the Everest ecosystem in Nepal, is one of the most ecologically diverse regions in the Himalayas. Spanning over 7,000 meters in elevation, it harbors some of the last remaining pristine forests, supporting habitats from tropical to arctic zones. From April 2019 to March 2024, a camera trapping survey was conducted across eight locations within the valley, capturing 38,075 images of 30 mammal species (excluding small mammals and bats). Among these, seven are globally threatened, and five species were photographed for the first time in the park. Additionally, some mammals were recorded at unusual elevation ranges, highlighting the valley’s ecological significance. Despite its remoteness, the Barun Valley faces increasing anthropogenic pressures. Key threats include habitat encroachment due to black cardamom cultivation, poaching, a proposed hydropower project at the heart of the park, and road construction in the park’s buffer zone, linking Tibet and India. Furthermore, a lack of awareness among local communities exacerbates conservation challenges. Continuous monitoring is essential to assess climate change impacts on species distribution, ecological adaptations, and human-wildlife interactions. Strengthening community awareness and enforcing conservation measures are critical to preserving this unique and sacred landscape for future generations.