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 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 km (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, with an average January temperature of -4 °C. Tromsø is still quite cool in the summer, with a 24-hour average of 12 °C and average daily high of 15°C in July.
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 League.
Despite only being home to around 80 people, Tromsø was issued its city charter in 1794. However, the city quickly rose in importance. The diocese of Hålogaland was created in 1804, with the first bishop being Mathias Bonsach Krogh. A teacher training college and the first shipyard were established in 1848, followed by the predecessor of the University of Tromsø, the Tromsø Museum, in 1872, and the Mack Brewery in 1877.
In the 19th century, Tromsø was known as the "Paris of the North", probably because people in Tromsø appeared as far more civilized than expected to foreign tourists.
Arctic hunting, from Novaya Zemlya to Canada, started up around 1820. By 1850, Tromsø was the major center of Arctic hunting, overtaking the former center of Hammerfest, and the city was trading from Arkhangelsk to Bordeaux. By the end of the 19th century, Tromsø had become a major Arctic trade center from which many Arctic expeditions originated. Explorers like Roald Amundsen, Umberto Nobile and Fridtjof Nansen made use of the know-how in Tromsø on the conditions in the Arctic, and often recruited their crew in the city. The Northern lights observatory was founded in 1927.
During World War II, it served briefly as the seat of Norwegian government. However, the city escaped the war without any damage, although the German battleship Tirpitz was sunk off the Tromsøy island on 12 November 1944, when close to 1,000 German soldiers died. At the end of the war, the city received thousands of refugees from the Finnmark province, which was evacuated and devastated by German forces at the time in expectation of the Red Army offensive.
Expansion after World War II has been rapid. The population growth has been strong, some years more than 1,000 people. The present municipal borders were created through the merger of Tromsø, Hillesøy, Tromsøysund and most of Ullsfjord in 1964, almost tripling the population from 12,430 to 32,664. Tromsø Airport opened in 1964, the University of Tromsø in 1972 and the Norwegian Polar Institute was relocated to Tromsø from Oslo in 1998.
The Sámi name of the island, Romsa, is assumed to be a loan from Norse - but according to the phonetical rules of the Sami language the frontal t has disappeared from the name. However, an alternative form - Tromsa - is in informal use. There is a theory that holds the Norwegian name of Tromsø derives from the Sámi name, though this theory lacks an explanation for the meaning of Romsa. A common misunderstanding is that Tromsø's Sámi name is Romssa with a double "s". This, however, is the accusative and genitive form of the noun - used when, for example, writing "Tromsø Municipality" (Romssa Suohkan).
The original reindeer coat-of-arms design is from 1870. The current version was created by Hallvard Trætteberg (1898–1987) and was adopted in 1941. Tromsø's coat-of-arms is one of six Norwegian coat-of-arms showing reindeer or their antlers, the other five being those of Eidfjord, Porsanger, Rendalen, Vadsø and Vågå.
The city center is located on the east side of the Tromsøya — over 300 km inside the Arctic Circle at . Suburban areas include Kroken, Tromsdalen (on the mainland, east of the Tromsøya island), the rest of the Tromsøya island, and the eastern part of the large Kvaløya, west of the Tromsøya Island. Tromsø Bridge and a four laned road tunnel connects the mainland with Tromsøya by road, and, on the western side of the city, Sandnessund Bridge connects Tromsøya island with Kvaløya island.
The midnight sun is above the northern horizon from about 18 May to 26 July, although the mountains in the north block the view to the midnight sun a few days, meaning that one can see the sun from about 21 May to 21 July. Due to Tromsø's position near the top of the globe, twilight is longer, meaning there is no real darkness between late April and mid August.
The sun remains below the horizon from about 26 November to 15 January, but due to the mountains the sun is absent from the center from 21 November to 21 January. The return of the sun is an occasion for celebration. Due to the twilight, there is some daylight for a couple of hours even around midwinter, often with beautiful bluish light. The nights shorten quickly, and by 21 February the sun is above the horizon from 07:45 to 16:10, and 1 April from 05:50 to 19:50 (summertime).
The combination of snow cover and sunshine often creates intense light conditions from late February until the snow melts in the lowland (usually late April), and sunglasses are essential when skiing. Because of these diametrically different light conditions in winter, Norwegians often divide it into two seasons: Mørketid (the dark time) and Seinvinter (late winter).
Tromsø is in the middle of the Aurora Borealis (northern lights) zone, and is in fact one of the best places in the world to observe this phenomenon. Because of the planet's rotation, Tromsø moves into the aurora zone around 6 pm, and moves out again around midnight. Due to the light, no aurora is visible between late April and mid August.
The Polar Museum, situated in a wharf house from 1837, presents Tromsø's past as a center for Arctic hunting and starting point for polar expeditions. The Tromsø Cathedral, Norway's only wooden cathedral, built in 1861, is located in the middle of the city, and so is the small Catholic church Vår Frue. Norway's oldest cinema is still in use, Verdensteatret, was built in 1915-16. The cinema has large wall paintings, made by the local artist Sverre Mack in 1921, that picture scenes from Norwegian folk lore and fairy tales.
The Arctic Cathedral, a modern church from 1965, is situated on the mainland, facing the sound and city centre. The church, in reality a parish church and not a cathedral, was drawn by Jan Inge Hovig and is probably the most famous landmark in Tromsø. The aquarium and experience center Polaria from 1998 is a short walk south from the city center. The Tromsø Museum is a university museum, presenting culture and nature of North Norway. The museum also displays the Arctic-alpine botanic garden, the world's northernmost botanical garden. A cable car goes up to mount Storsteinen, 421 metres above sea level, with a panoramic view over Tromsø. The mountain Tromsdalstinden, 1238 m, on the mainland, which is easily spotted from the city center, is also a major landmark. On top of Tromsøya is lake Prestvannet.
The largest political party is the Labour Party. Although the Labour Party is led by Roger Ingebrigtsen, Labour's Arild Hausberg is mayor. The vice-mayor is Gunhild Johansen, from the Socialist Left Party.
More than 100 nationalities are represented in the population, among the more prominent minorities are the Sami, Russians, and Finns, both the local Kvens and immigrants from Finland proper. The world's northernmost mosque is to be found in Tromsø. The Our Lady Catholic church is the seat of the world's northernmost Catholic Bishop, although the Catholic population is only 350 heads strong — it is in this context interesting to note that Pope John Paul II visited this small church and stayed as a guest of the bishop in 1989.
The combined capacity of clubs, pubs, and bars is of more than 20,000 people, meaning that one out of three can go out at the same time. Rorbua achieved national fame when hosting the popular TV show Du skal høre mye, which ran for sixteen years, making it one of the most seen entertainment shows in the history of the Norwegian Broadcasting Corporation.
Many cultural activities take place in Kulturhuset (English: lit. culture house), including concerts by Tromsø Symphony Orchestra and plays by Tromsø's professional theater troupe, Hålogaland Teater. The new theater building was opened in November 2005. The city contains several museums. The largest are the Northern Norwegian Art Gallery (Nordnorsk Kunstmuseum) and the Tromsø Gallery of Contemporary Art (Tromsø Kunstforening).
Tromsø was a leading city at the early stages of the house and techno scene in Norway from the last part of the 1980s. Local artists such as Bel Canto, Biosphere, Mental Overdrive, Ismistik/Bjørn Torske, Aedena Cycle, Y.B.U., Open Skies, Alanïa, Those Norwegians, Phonophani, Lene Marlin, Drum Island and lately Röyksopp have all made their marks internationally. The Insomnia Festival pays tribute to this and seeks to profile relevant electronic music.
The Bukta Tromsø Open Air Festival, held in June and July, is a popular music festival that started three years ago as a merger between the smaller non-profit festival "North of Nowhere" and the "Fucking North Pole Punk Rock Festival". The Bukta festival is mainly a rock festival, but also features other kinds of modern music. The festival takes place in Telegrafbukta, a park on the south-western part of the Tromsøya island. Other popular cultural summer events among the population of Tromsø is the Karlsøy festival and the Riddu Riddu festival, both held in the region surrounding the city.
Tromsø is the home of many football (soccer) clubs, of which the three most prominent are Tromsø IL, which plays in the Norwegian Premier League and is the world's northermost Premier League football team, I.F. Fløya in the Norwegian Premier League for women, and Tromsdalen U.I.L., playing in the Adeccoliga. Tromsø Midnight Sun Marathon is arranged every year in June and recently also a Polar Night Half marathon in January. The city is home to many clubs in the top division in various sports. Most notably basketball-outfit Tromsø Storm in the BLNO, BK Tromsø in the top volleyball league for men, and Tromsø Volley in the top volleyball league for women.
Tromsø has been selected by the Norwegian National Olympic Committee as Norway's candidate for the 2018 Winter Olympics. This would make Tromsø the first city north of the Arctic Circle to host the games. There are plans to use ships as the media village. As of March 2007, the Norwegian government still has yet to officially support Tromsø's bid. From the southern to the northern tip of the island Tromsøya, there is a floodlit cross country ski track. A ski jump is also situated on the island, close to the university.