Viking-age Ánslo grew into Norway’s Beta-ranked capital
Oslo is Norway’s capital and largest city—a municipality-county with 724,290 residents in 2025, about 1.11 million in the urban area and roughly 1.5 million metro. Founded as Ánslo near the Viking Age’s end in 1040 and made a trading kaupstad in 1048 by Harald Hardrada, it later became capital under Haakon V.
Oslo, Norway's capital and most populous city, is at once a county and a municipality. The municipality counted 724,290 people on 1 January 2025, the wider urban area 1,110,887 that year, and the metropolitan area about 1,546,706. Suburbs in Akershus such as Asker, Bærum, Lillestrøm and Lørenskog add around 500,000 residents. From its centre at the head of the Oslofjord, building spreads along three corridors, northeast inland and south down each shore, tracing an upside-down reclining "Y".
The district belonged to Viken in the Viking Age. The town was founded as Ánslo in 1040, and Harald Hardrada made it a kaupstad, or trading place, in 1048. It gained a bishop in 1070 and became capital under Haakon V around 1300, though unions with Denmark from 1397 to 1523 and from 1536 to 1814 sapped its standing. After a fire in 1624, Christian IV rebuilt it nearer Akershus Fortress and named it Christiania.
It became a municipality on 1 January 1838 and served as capital throughout the 1814–1905 union with Sweden. Government usage spelled the name Kristiania from 1877, and the municipality adopted that form in 1897. Population rose at record pace in the early 2000s, making Oslo Europe's fastest-growing major city, driven mainly by immigration and higher birth rates plus internal migration; by 2010 residents of immigrant background, counting children of immigrant parents, exceeded 25% in the city proper.
The capital concentrates Norwegian government, trade, banking, industry and shipping, and hosts some of the world's biggest shipping firms, shipbrokers and marine insurance brokers. It is a pilot city in the Council of Europe and European Commission intercultural cities programme. GaWC rated it a Beta World City in 2008, and fDi magazine's 2012 European Cities of the Future report put it first for quality of life among large European cities. Living there is costly: ECA International placed it second behind Tokyo in 2011, and in 2013 the Economist Intelligence Unit had it tied with Melbourne for fourth.
Source: Oslo
