oslo

Oslo is the capital and most populous city of Norway. It constitutes both a county and a municipality. The municipality of Oslo had a population of 724,290 in 2025, while the city's greater urban area had a population of 1,110,887 in 2025, and the metropolitan area had an estimated population of 1,546,706 in 2021.

During the Viking Age, the area was part of Viken. Oslo was founded as a city at the end of the Viking Age in 1040 under the name Ánslo, and established as a kaupstad or trading place in 1048 by Harald Hardrada. The city was elevated to a bishopric in 1070 and a capital under Haakon V of Norway around the year 1300. Personal unions with Denmark from 1397 to 1523 and again from 1536 to 1814 reduced its influence. After being destroyed by a fire in 1624, during the reign of King Christian IV, a new city was built closer to Akershus Fortress and named Christiania in honour of the king. It became a municipality (formannskapsdistrikt) on 1 January 1838. The city functioned as the capital of Norway during the 1814–1905 union between Sweden and Norway. From 1877, the city's name was spelled Kristiania in government usage, a spelling that was adopted by the municipal authorities in 1897, although 'Christiania' was also used. In 1925, the city, after incorporating the village retaining its former name, was renamed 'Oslo'. In 1948, Oslo merged with Aker, a municipality which surrounded the capital and which was 27 times larger, thus creating the modern, much larger Oslo municipality.