Mustang District a part of Dhaulagiri Zone, is one of the seventy-five districts of Nepal, a landlocked country of South Asia. The district, with Jomsom as its headquarters, covers an area of 3,573 km² and has a population (2001) of 14,981.

The district straddles the Himalayas and extends northward onto the Tibetan plateau. Upper Mustang, the former Lo Kingdom comprises the northern two-thirds of the district. This kingdom was a dependency of the Kingdom of Nepal but was abolished by the republican Government of Nepal on October 7, 2008.

In addition to trekking routes through the Lo Kingdom ("Upper Mustang") and along the Annapurna Circuit in lower Mustang, the district is famous for the springs and village of Muktinath (a popular Hindu and Buddhist pilgrimage site), apples, and Marpha brandy. Mustang was a lost kingdom of Tibet where traditions may remain more Tibetan than in Tibet proper following its annexation by China.

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