Landlocked Bhutan is situated in the eastern Himalayas and is mostly mountainous and heavily forested. It is bordered by Tibet (China’s Xizang Autonomous Region) to the north and northwest and by the Indian states of Sikkim to the west, West Bengal to the southwest, Assam to the south and southeast, and Arunachal Pradesh to the east.
One of the most rugged mountain terrains in the world, it has elevations ranging from 160 meters to more than 7,000 meters above sea level. Gangkhar Puensum is the highest mountain in Bhutan and the highest unclimbed mountain in the world with an elevation of 7,570 metres. The second highest peak, Chomo Lhari, overlooking the Chumbi Valley in the west, is 7,314 meters above sea level; nineteen other peaks exceed 7,000 meters.
Watered by snow-fed rivers, alpine valleys in this region provide pasturage for livestock tended by a sparse population of migratory shepherds.
The Inner Himalayas are southward spurs of the Great Himayalan Range. The Black Mountains, in central Bhutan, form a watershed between two major river systems, the Mo Chhu and the Drangme Chhu (chhu means river). Peaks in the Black Mountains range between 1,500 meters and 2,700 meters above sea level, and the fast-flowing rivers have carved out spectacular gorges in the lower mountain areas. The woodlands of the central region provide most of Bhutan’s valuable forest production. Eastern Bhutan is divided by another southward spur, the Donga Range. Western Bhutan has fertile, cultivated valleys and terraced river basins.
In the south, the Southern Hills, or Siwalik Hills, the foothills of the Himalayas, are covered with dense deciduous forest, alluvial lowland river valleys, and mountains that reach to around 1,500 meters above sea level. The foothills descend into the subtropical Duars Plain. The Bhutan Duars has two parts. The northern Duars, which abuts the Himalayan foothills, has rugged, slopping terrain and dry porous soil with dense vegetation and abundant wildlife. The southern Duars has moderately fertile soil, heavy savanna grass, dense mixed jungle, and freshwater springs. Taken as a whole, the Duars provides the greatest amount of fertile flatlands in Bhutan. Rice and other crops are grown on the plains and mountainsides up to 1,200 meters. Bhutan’s most important commercial centers– Phuntsholing, Geylegphug, and Samdrup Jongkhar–are located in the Duars, reflecting the meaning of the name, which is derived from the Hindi dwar and means gateway. Rhinoceros, tigers, leopards, elephants, and other wildlife inhabit the region.