A high country, Mongolia has an average elevation exceeding 5,100 ft (1,554 m); the central, northern, western, and southwestern areas are covered with hills, high plateaus, and mountain ranges, reaching 15,266 ft (4,653 m) at Tavan Bogd Uul (Tabun Bogdo) in the Altai Mts. Much of the Gobi desert lies to the south and east; at no point is the elevation less than c.1,800 ft (550 m). Numerous lakes fill the depressions between the mountains; the largest, Uvs Nuur, or Ubsu Nur (c.1,300 sq mi/3,370 sq km) is saltwater. The main rivers are in the north and include the Selenga (Selenge Mörön), with its long tributary the Orkhon (Orhon), which flows into Lake Baykal in Russia; and the Kerulen. Navigability is limited—the rivers are swift and rough; they freeze in the winter, and many dry up during droughts.
The country's climate is dry continental, with little rain or snow and great extremes in temperature. Winters are severe, with low temperatures and high winds that blow away the light snow cover, causing the ground to freeze deeply; summers can be very hot.
The population is predominantly Khalkha Mongol. Minorities include Oirat Mongols, Kazakhs, Chinese, and Russians. Khalkha Mongolian, the official language, was until the 1940s written in the old Uigur Turkic script; it now uses the Cyrillic alphabet. Turkic, Russian, and Chinese are also spoken by some. The dominant religion has long been Lamaist Buddhism, but it was harshly repressed under the Communist regime. It was not until the waning of Communist power in the early 1990s that religious freedom reemerged. There are also small Muslim and Christian minorities.