The Upper Arun valley lies on the eastern edge of the Makalu-Barun National Park and Buffer Zone in north east Nepal (Sankhuwasabha District). Locally known as the Bhotkhola, this region was closed to foreign visitors until 2003 and still remains one of the most remote and least visited areas. Travel here is exclusively on foot and involves 6-8 days of strenuous trekking from the District Headquarters at Khandbari to the border of the Tibetan Autonomous Region (China).