Mustang (from Tibetan Mun Tan (Wylie smon-thang) which means fertile plain) is the former Kingdom of Lo and now part of Nepal, in the north-central part of that country, bordering Tibet on the Central Asian plateau between the Nepalese provinces of Dolpo and Manang. The Kingdom of Lo, the traditional Mustang region, and "Upper Mustang" are one and the same, comprising the northern two-thirds of the present-day Nepalese Mustang District, and are well marked by official "Mustang" border signs just north of Kagbeni where a police post checks permits for non-Nepalese seeking to enter the region, and at Gyu La (pass) east of Kagbeni.
Life in Mustang revolves around tourism, animal husbandry and trade. Mustang is also known as "Tibet outside the Tibetan Border" for it survived the Chinese invasion of 1951 and hence fosters much original Tibetan culture, although it is now politically part of Nepal and, except for a nine km portion from Chhusang to Syangboche (just south of Ghiling (Geling)) as of August 2010, it is bisected by a new road linking it to Tibet to the north and to the rest of Nepal to the south. Plans call for the final nine km portion to be completed in just a few years' time, which will provide, with a high point of 4660 m at Kora La on the Mustang-Tibet border, the lowest drivable corridor through the Himalayas linking the Tibetan Plateau via Nepal to the tropical Indian plains. (The easiest and only widely used road corridor, from Kathmandu to Lhasa via the Arniko Rajmarg (or Arniko Highway, traverses a 5125 m pass.)
Mustang was once an independent kingdom, although closely tied by language and culture to Tibet. From the 15th century to the 17th century, its strategic location granted Mustang control over the trade between the Himalayas and India. At the end of the 18th century the kingdom was annexed by Nepal.
Though still recognized by many Mustang residents, the monarchy officially ceased to exist on October 7, 2008, by order of the Government of Nepal. The last official and current unofficial king (raja or gyelpo) is Jigme Dorje Palbar Bista (born.1933), who traces his lineage directly back to Ame Pal, the warrior who founded this Buddhist kingdom in 1380. Ame Pal oversaw the founding and building of much of the Lo and Mustang capital of Lo Manthang, a walled city surprisingly little changed in appearance from that time period.
Mustang is largely dry and arid with annual precipitation in the range of 250–400 mm) due to its position in the rain shadow of the Annapurna massif and the Dhaulagiri Range towards the south.
The population of Mustang District in 2001 was 14,981, spread between three towns and approximately thirty smaller settlements; the people are either Thakalis, Gurung or, in traditional Mustang, primarily Tibetan.
Most of the population of Mustang lives near the Kali Gandaki River, 2800–3900 m above sea level. The tough conditions cause a large winter migration into lower regions of Nepal. The administrative centre of Mustang District is at Jomsom (eight km south of Kagbeni) which has had an airport since 1962 and has become the main tourist entry point since Mustang was opened to western tourism in 1992.
The main hydrographic feature of Mustang is the Kali Gandaki River. The river runs southward towards Nepal Terai, bisecting Mustang. Routes paralleling the river once served as a major trade route between Tibet and India, especially for salt. Part of the river valley in the southern Mustang District forms by some measures the deepest gorge in the world. Traditional Mustang (the Lo Kingdom) is 53 km north-south at its longest and 60 km east - west at its widest, and ranges from a low point of 2750 m above sea level on the Kali Gandaki River just north of Kagbeni to 6700 m (Khamjung Himal, a peak in southeast Mustang.)