Trondheim, historically Kaupangen, Nidaros, and Trondhjem, is a city and municipality in Trøndelag county, Norway. As of January 1, 2026, it had a population of 218,460. Trondheim is the third most populous municipality in Norway, and is the fourth largest urban area. Trondheim lies on the south shore of Trondheim Fjord at the mouth of the River Nidelva. Among the significant technology-oriented i…