It is the largest city and the largest urban area in Northern Norway, and the second largest city and urban area north of the Arctic Circle in Sápmi (following Murmansk). Most of Tromsø, including the city centre, is located on the small island of Tromsøya in the county of Troms, 350 kilometres (217 mi) north of the Arctic Circle. Substantial parts of the urban area are also situated on the mainland to the east, and on parts of Kvaløya—a large island to the west. Tromsøya is connected to the mainland by the Tromsø Bridge and the Tromsøysund Tunnel, and to the island of Kvaløya by the Sandnessund Bridge. The city is warmer than most other places located on the same latitude, due to the warming effect of the Gulf Stream.
The city centre of Tromsø contains the highest number of old wooden houses in Northern Norway, the oldest house dating from 1789. The Arctic Cathedral, a modern church from 1965, is probably the most famous landmark in Tromsø. The city is a cultural centre for its region, several festivals taking place in the summer.
The area has been inhabited since the end of the ice age. In Tønsvika, just outside the city limits, traces of a settlement from late stone age (4000–1800 BC) have been found.
Tromsø is the eighth-largest municipality in Norway with a population 69,116, and the centre of the ninth-largest urban area, with a population of 58,486. The city is home to the world's most northerly university and also houses the most northerly botanical garden and planetarium.