Geographically, Nepal comprises three major areas. The south, known as the Terai, is a comparatively low region of cultivable land, swamps, and forests that provide valuable timber. In the north is the main section of the Himalayas, including Mt. Everest (29,029 ft/8,848 m), the world's highest peak. Nepal's major rivers, which rise in Tibet, rush through deep Himalayan gorges. Central Nepal, an area of moderately high mountains, contains the Katmandu valley, or Valley of Nepal, the country's most densely populated region and its administrative, economic, and cultural center. Nepal's railroads, connecting with lines in India, do not reach the valley, which is served by a highway and a bridgelike cable line. There are a few other modern highways.
The population of Nepal is the result of a long intermingling of Mongolians, who migrated from the north (especially Tibet), and peoples who came from the Ganges plain in the south. The chief ethnic group, the Newars, were probably the original inhabitants of the Katmandu valley. Other groups include the Chettris, Brahmans, Magars, Tharus, and Gurungs. Several ethnic groups are classified together as Bhotias; among them are the Sherpas, famous for guiding mountain-climbing expeditions, and the Gurkhas, a term sometimes loosely applied to the fighting castes, who achieved fame in the British Indian army and continue to serve as mercenaries in India's army and in the British overseas forces. Nepali, the country's official language, is an Indo-European language and has similarities to Hindi. Tibeto-Burman languages, Munda languages, and various Indo-Aryan dialects are also spoken. About 80% of the people are Hindu, about 10% are Tibetan Buddhists (see Tibetan Buddhism), and there are smaller groups of Muslims and others. Tribal and caste distinctions are still important. The royal family is Hindu, and until 2006 the country was officially a Hindu kingdom. The entrenched caste system and rural poverty provided fertile ground for the Maoist insurgency that began in the 1990s.