The area has been inhabited since the end of the ice age, and the Sámi culture is the first known culture of the region. Speakers of Norse, the ancestor of Norwegian brought their culture to the area during the migrations of the Vikings before AD 890, when Ohthere's settlement existed to the south of today's Tromsø. The first church on the island of Tromsøya was erected in the 13th century, and the area one of Denmark-Norway's very northernmost territories not contested by Russia. During the 1600s, Denmark-Norway solidified its claim to the northern coast of Scandinavia and during this period a redoubt, Skansen, was built. Tromsø was issued its city charter in 1794 by King Christian VII. The city was established as a municipality 1 January 1838 (see formannskapsdistrikt). The rural municipalities of Tromsøysund and Ullsfjord, and most of Hillesøy, were merged with Tromsø on 1 January 1964. The population of Tromsø municipality is 63,596, and the urban area, Norway's ninth most populous, is home to 53,622 people.

Most of Tromsø, including the city centre, is located on the small island of Tromsøya in the county of Troms, 350 kilometres (217 mi) inside the arctic circle. The island 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 North 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 largest football team in the city, Tromsø I.L, plays in the Norwegian Premier