Ulan Bator, formerly Urga, city in north central Mongolia, is the capital of the Republic of Mongolia. The city is situated in a valley at an elevation of about 1310m and is surrounded by ridges. It is the political, cultural, industrial, and transportation center of the country, connected by highway to all the major towns in Mongolia and by rail to the Trans-Siberian and Chinese railroad systems.

Manufactures include construction materials, footwear, clothing, leather goods, machine tools, dairy products, pharmaceuticals, and porcelain. Meat plants, a brewery, and a power station are in operation. Important lignite mines are nearby.

After World War II (1939-1945) the city expanded greatly, largely with the aid of planning from former Soviet Union. The broad tree-planted boulevards and squares of the city are lined with ponderous neoclassical buildings. In the city are the State Public Library, several museums, the National Theater, Mongolian State University (1942), and the country's academy of sciences. Also notable is the Monastery of the Living Buddha, the residence of the nation's former spiritual leader, now a museum.

The city was founded in 1649 as a monastery center and eventually became the seat of the Living Buddha. In the mid-19th century it developed as an important commercial center on the trade route between Russia and China. The city became capital of newly independent Outer Mongolia in 1911, and in 1921 it was taken by a Mongolian revolutionary group aided by Soviet forces. When in 1924 the Communist Mongolian People's Republic was established, the city was renamed Ulaanbaatar (Mongolian for ¡°Red Hero¡±). Population (1999 estimate) 665,800.

Ulan Bator and Huhhot, capital of China Inner Mongolia Autonomous Region, as well as Tianjin, China, are sister cities respectively.