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 …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 709,037 in 2022, while the city's greater urban area had a population of 1,064,235 in 2022, and the metropolitan area had an estimated population of 1,546,706 in 2021.