city of county status and seat of Komárom-Esztergom megye (county), northwestern Hungary. Lying in the valley of the Gallei River, between the Vértes Hills to the south and the Gerecse Mountains to the northeast, the city was once Hungary's main mining centre and is located on the country's largest lignite deposit, the Tatabánya-Oroszlány Basin. Mining began there on the outskirts of the existing settlements, including Felsőgalla, Alsógalla, Bánhida, and others, which were incorporated into Tatabánya in 1902, when it was given the status of a separate village. There is a limestone quarry and marlpit, and there are two large thermoelectric-power stations. The mining and manufacturing that dominated the economy in the 20th century declined rapidly after the political changes of the 1990s.

The settlements of which Tatabánya was constituted stretch out approximately 7 mi (11 km) in length. The newest district, Ujváros (“New Town”), is on the west. Tatabánya has road and rail connections with Budapest, 35 mi (56 km) to the east. Pop. (2001) 72,470.