Himalayas, a mountain system in southern Asia, the highest in the world. It is about 1,500 miles (2,400 km) long and about 100 to 150 miles (160 to 240 km) wide. The mountains form a massive barrier between the Plateau of Tibet on the north and the Indian subcontinent on the south.
The Himalayas—the name is Sanskrit for “abode of snow”—contain dozens of peaks exceeding 20,000 feet (6,100 m) above sea level. Mount Everest, on the Nepal-China border, reaches 29,035 feet (8,850 m) and is the world's highest peak. Kanchenjunga, Makalu, Dhaulagiri, Nanga Parbat, and Annapurna are other prominent peaks; all exceed 25,000 feet (7,620 m). Most of the passes through the Himalayas lie above 15,000 feet (4,600 m).
The Himalayas make up the central part of an enormous mountain belt, the ends of which include the towering Pamirs and the Karakoram and Hindu Kush ranges on the west and the lower ranges of the Indochinese Peninsula on the east. Like the Alps and the Andes, the Himalayas are geologically young. Earthquakes are numerous and sometimes violent. Many geologists believe the mountains are still growing.
The Himalayas rise abruptly from the low plains of the Indian subcontinent. They consist of three almost parallel ranges. From south to north and increasing in height, they are the Siwalik Hills, the Lesser Himalayas, and the Great Himalayas. Farther north is a fourth range, the Trans-Himalayas; these mountains are not considered part of the Himalayas.
Only occasionally do either the dry, bitterly cold winters of central Asia or the moist, subtropical summers of eastern India extend beyond the mountain barrier. Because of humid monsoon winds from the Bay of Bengal during summer, the south-facing slopes of the eastern Himalayas are rainy and heavily forested. The western section, lying farther inland and less affected by the winds, is relatively dry and barren. Vegetation varies greatly. There are tropical rain forests in some eastern lowland valleys while vegetation in the high mountains is like that of the arctic tundra.
The Indus, Ganges, and Brahmaputra rivers, along with most of their chief tributaries, drain the Himalayas. The rivers are used mainly for irrigation, water power, and navigation on the plains to the south.
Except for southern foothills and valleys, the mountains are sparsely inhabited. Caucasoid people predominate in Kashmir and northern India, Mongoloid people elsewhere. They live mainly by farming, hunting, and the grazing of sheep and goats. Around Darjeeling, tea is grown on large plantations. No railways and few roads cross the Himalayas; trade is limited; and mineral and forest resources are largely untouched. Chief cities include Srinagar, in Kashmir; Simla and Darjeeling, in India; and Kathmandu, Patan, and Bhadgaon, in Nepal.