[1] In addition is Marka (1610 residents), that is administered by several boroughs; and Sentrum (1471 residents, 1.8 km2) that is partially administered by St. Hanshaugen, and in part directly by the city council.
As of 1 January 2020, Oslo had 693,494 residents, of which 2386 were not allocated to a borough.
Some existed only on paper, since they were to be constituted only when the areas were built.
From 1985 to 1988, the boroughs of Stovner, Røa, Gamle Oslo and Søndre Nordstrand were trials for the new system.
From 1 July 1988 to 31 December 2003, Oslo had 25 boroughs: In addition Sentrum and Marka.