Trondheim ( TRON(D)-hyme; Urban East Norwegian: [ˈtrɔ̂nː(h)æɪm]; Southern Sami: Tråante), historically Kaupangen, Nidaros, and Trondhjem (locally [ˈtrɔ̂nːjæm] ⓘ), is a city and municipality in Trøndelag county, Norway. As of 1 January 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 Nidelva. Among the significant technology-oriented institutions headquartered in Trondheim are the Norwegian University of Science and Technology (NTNU), the Foundation for Scientific and Industrial Research (SINTEF), the Geological Survey of Norway (NGU), and St. Olavs University Hospital.
The settlement was founded in 997 as a trading post and served as the capital of Norway through the Viking Age until 1217. From 1152 to 1537, the city was the seat of the Catholic Archdiocese of Nidaros; it then became, and has remained, the seat of the Lutheran Diocese of Nidaros and the site of the Nidaros Cathedral. The city was incorporated in 1838. The current municipality was formed in 1964, when Trondheim merged with Byneset Municipality, Leinstrand Municipality, Strinda Municipality, and Tiller Municipality, and further expanded on 1 January 2020, when Trondheim merged with Klæbu Municipality.
Trondheim has a mild climate for its northerly latitude, resulting in moderate summers and winters that often remain above the freezing point in seaside areas. At higher elevations, though, the microclimate is colder and snowier.
The city functions as the seat of the County Mayor of Trøndelag county but not as its administrative centre (which is Steinkjer). This is designed to avoid making the county administration too centralized.
Trondheim is home to football club Rosenborg, Norway's most successful football club, and Granåsen Ski Centre, which has hosted the World Championship in Nordic skiing.
Names and etymology
The city was established in 997 by Olav Tryggvason and it was originally named Nidaros (Old Norse: Niðaróss). The first element of the name was the local river Nid. The last element of the name was óss 'mouth (of a river)'. Thus the name meant 'the outlet of the river Nid'. Although the formal name was Nidaros, the city was commonly known as kaupangr 'city; marketplace', or more specifically kaupangr í Þróndheimi 'the city in Trondheim'. Trondheim (Old Norse: Þróndheimr) was the historic name for the whole district which is now known as Trøndelag. This is the area where the people were known as Trønder (þróndr). This district name Trondheim meant 'the home of the Trønder people' (lit. 'Trønder-home') and Trøndelag (Old Norse: Þrǿndalǫg) originally meant the 'law area of the Trønder people' (lit. 'Trønder-law'). The name of the Trønder people derives from the Old Norse word þróndr, an old present participle of the verb þróask 'to grow, thrive'.
During the late Middle Ages, the city name was commonly shortened to Þróndheimr, dropping the kaupanger part, and over time the name became Trondhjem, using the Dano-Norwegian spelling rather than the Old Norse spelling since the city was part of the Kingdom of Denmark-Norway for centuries.
On 21 December 1917, a royal resolution enacted the 1917 Norwegian language reforms. Around the time, many municipalities and cities had their names changed to "Norwegianize" the spelling and make them look less Danish. On 1 January 1919, the name of the local Church of Norway diocese was changed from Trondhjem stift to Nidaros bispedømme (English: Diocese of Nidaros). In 1924, the name of the Norwegian capital city was changed from Kristiania to Oslo, removing the name referencing a Danish King in favor of the very old name Oslo. In 1928, a referendum in Trondhjem was held on whether to keep the current name or to bring back the original name of Nidaros. The vote resulted in 17,163 votes in favour of Trondhjem and only 1,508 votes in favour of Nidaros. Despite this result, the Storting voted in 1929 to make some changes. The Trondhjem Cathedral would be changed to Nidaros Cathedral effective on 1 July 1929 and the name of the city would change to Nidaros starting on 1 January 1930. This change caused public outrage and even riots during 1930. This forced the Storting to reconsider this change. On 6 March 1931, the name was formally changed to Trondheim, using the medieval Norwegian spelling instead of the Danish version Trondhjem. The name of the diocese and cathedral, however, continued using the name Nidaros.
Trondheim was briefly named Drontheim during the Second World War as a German exonym.
History
Trondheim was named Kaupangen (English: market place or trading place) by Viking King Olav Tryggvason in 997 CE. Shortly after that, it came to be called Nidaros. Initially, it was frequently used as a military retainer (Old Norse: "hird"-man) of King Olav I. It was also frequently used as the king's seat and was Norway's capital until 1217.
People have lived in the area for thousands of years, as evidenced by the rock carvings in central Norway, the Nøstvet and Lihult cultures, and the Corded Ware culture. In ancient times, the kings of Norway were hailed in Trondheim at Øretinget, the place for the assembly of all free men by the mouth of the River Nidelva. Harald Fairhair (865–933) was hailed as the king here, as was his son, Haakon I, called 'the Good.' The battle of Kalvskinnet took place in Trondheim in 1179: King Sverre Sigurdsson and his Birkebeiner warriors were victorious against Erling Skakke (a rival to the throne). Some scholars believe that the famous Lewis chessmen, 12th-century chess pieces carved from walrus ivory that were found in the Hebrides and are now at the British Museum, may have been made in Trondheim.
From 1152, Trondheim was the seat of the Archbishop of Nidaros for Norway, which operated from the Archbishop's Palace. Due to the introduction of Lutheran Protestantism in 1537, the last archbishop, Olav Engelbrektsson, had to flee from the city to the Netherlands; he died in what today is Lier, Belgium.
From the 16th through the 19th centuries, the city was repeatedly ravaged by fires that caused widespread damage since many of its buildings were made of wood. The worst occurred in 1598, 1651, 1681, 1708, 1717 (twice), 1742, 1788, 1841 and 1842. The 1651 fire destroyed 90% of all buildings within the city limits. After the "Horneman Fire" in 1681, there was an almost total reconstruction of the city, overseen by General Johan Caspar von Cicignon, originally from Luxembourg. Broad avenues, such as Munkegata, were created, without regard for private property rights, to limit the damage from future fires. At the time, the city had a population of under 10,000 inhabitants, with most living in the downtown area.
After the Treaty of Roskilde on 26 February 1658, Trondheim and the rest of Trøndelag became Swedish territory briefly. However, after a three-month long siege, the area was reconquered 10 months later. The conflict was finally settled by the Treaty of Copenhagen on 27 May 1660.
During the Second World War, Trondheim was occupied by Nazi Germany from 9 April 1940, the first day of the invasion of Norway, until the end of the war in Europe, 8 May 1945. The German invasion force consisted of the German cruiser Admiral Hipper, 4 destroyers and 1700 Austrian Mountain troops. Except for a coastal battery that opened fire, there was no resistance to the invasion, which began on 9 April at 5 AM. On 14 and 17 April, British and French forces landed near Trondheim in a failed attempt to liberate Trondheim, as part of the Namsos Campaign. During the occupation, Trondheim was the home of the notorious Norwegian Gestapo agent, Henry Rinnan, who operated from a nearby villa and infiltrated Norwegian resistance groups. The city and its citizens were subjected to harsh treatment by the occupying power, including the imposition of martial law in October 1942. During this time, the Germans turned the city and its environs into a major base for submarines (which included building the large submarine base and bunker DORA I), and contemplated a scheme to build a new city for 300,000 inhabitants, Nordstern ("Northern Star"), centred 15 kilometres (9 miles) southwest of Trondheim, near the wetlands of Øysand on the outskirts of Melhus municipality. This new metropolis was to be accompanied by a massively expanded version of the already existing naval base, which was intended to become the future primary stronghold of the German Kriegsmarine. A start was made on this enormous construction project, but it was far from completed when the war ended, and today, there are few physical remains of it.
Municipal history
The city of Trondheim was established on 1 January 1838 (see formannskapsdistrikt law). On 1 January 1864, part of Strinda Municipality (population: 1,229) was amalgamated with Trondheim. Then, on 1 January 1893, another part of Strinda Municipality (population: 4,097) was transferred to Trondheim Municipality. On 1 January 1952, the Lade area of Strinda Municipality (population: 2,230) was transferred to Trondheim Municipality. On 1 January 1964, a major municipal merger took place: Leinstrand Municipality (population: 4,193), Byneset Municipality (population: 2,049), Strinda Municipality (population: 44,600), and Tiller Municipality (population: 3,595) were all merged with the city of Trondheim (population: 56,982), which nearly doubled the population of the municipality. On 1 January 2020, the neighboring Klæbu Municipality (population: 6,050) was merged with Trondheim Municipality.
Coat of arms and seal
The coat of arms dates back to the 13th century. To the left, there is an archbishop with his staff and mitre in a church archway. On the right, a crowned king holding scales in a castle archway. These two pictures rest on a base which forms an arch. Underneath that arch, are three male heads which symbolise the city's rank as Norway's first capital and the archbishop's place of residence. The scales symbolise justice and the motif is based on the political philosophy of the 13th century, where the balance of power between king and church was an important issue. The three heads at the bottom may symbolise the city council. The motif is unique in Norwegian municipal heraldry, but similar motifs are found in bishopric cities on the continent. The design of the coat-of-arms that was adopted in 1897, and is still used today, was made by Håkon Thorsen.
Geography
Trondheim is situated where the River Nidelva meets Trondheim Fjord with an excellent harbour and sheltered condition. In the Middle Ages the river was deep enough to be navigable by most boats. However, in the mid–17th century, an avalanche of mud and stones made it less navigable, and partly ruined the harbour. The municipality's highest elevation is the Storheia hill, 565 metres (1,854 ft) above sea level. At the summer solstice, the sun rises at 03:00 and sets at 23:40, and then stays just below the horizon. Between 23 May and 19 July, when the sky is cloud-free, it remains light enough at night that no artificial lighting is needed outdoors. At the winter solstice, the sun rises at 10:01, stays very low above the horizon (at midday its altitude is slightly more than 3 degrees over the horizon), and sets at 14:31.
Climate
Trondheim city has an oceanic climate (Cfb) or humid continental climate (Dfb), depending on the winter threshold used (−3°C or 0°C) and the location within the city. Winters are fairly cold and summers are mild. The part of the municipality further away from the fjord has slightly colder winters, while the part close to the fjord has the mildest winters. Trondheim is mostly sheltered from the strong south and southwesterly winds which can occur along the outer seaboard but is more exposed to northwesterly winds. As with the rest of Norway, the weather is dependent on the weather pattern. High pressure over Central Norway or to the east can last for weeks, while Atlantic Lows from the west also can dominate for weeks. Such stuck opposite weather patterns was evident in 2020, when May saw northwesterlies with cold air even bringing some snowfall, while the following June was warm and sunny. Trondheim experiences moderate snowfall from November to March, but mixed with mild weather and rainfall. There is often more snow and later snowmelt in suburban areas at a higher elevation, with good skiing conditions in Bymarka. All the monthly record lows are from 1955 or older, with half of them from before 1920. The last overnight frost in June was in 1958. The all-time low −26 °C (−14.8 °F) was recorded February 1899. The all-time high 35 °C (95 °F) was recorded 22 July 1901.
The earliest weather stations were located closer to the city centre, from 1945 onwards the weather station has been located at a higher elevation (Voll, 127 m and Tyholt, 113 m), therefore being slightly colder.
A new sunrecorder was established in the city by met.no at Gløshaugen (NTNU campus) December 2015, recording more sunhours than the earlier sunrecorder, which had terrain blocking issues. Trondheim recorded 197 sunhours in October 2016 beating the previous national record for October. In April 2019 Trondheim recorded 308 sunhours, new national record for April. In contrast, December 2016 only recorded 10 sunhours.
Located at 63 degrees north, Trondheim experience "white nights" with only civil twilight during the height of summer. This light allow for normal daytime activities at night, such as reading a book.
Fauna
The city has various wetland habitats. among which there is the Gaulosen. The observation tower accommodates for birdwatching and providing information about birdlife.