Trondheim , historically Kaupangen, Nidaros and Trondhjem, is a city and municipality in Sør-Trøndelag county, Norway. With a population of 181,513 (1 October 2013), it is considered to be the third most populous municipality in Norway, although the fourth largest urban area. It is also the third largest city in the country, with a population (2013) of 169,972 inhabitants within the city borders. The city functions as the administrative centre of Sør-Trøndelag county. Trondheim lies on the south shore of the Trondheimsfjord at the mouth of the river Nidelva. The city is dominated by the Norwegian University of Science and Technology (NTNU), SINTEF, St. Olavs University Hospital and other technology-oriented institutions.