Akerselva, or Akerselven, is a river which flows through Oslo. It starts at Maridalsvannet in Oslomarka, and follows the urban areas Nordre Aker, Sagene, Grünerløkka, Oslo centre and Grønland, whereby it finally ends at Paulsenkaien and Oset in Bjørvika. The river is considered to be a part of the Nordmarkvassdraget, and has the watercourse number 006.Z. The entire river is about 8.2 kilometres long, and has a difference in altitude of approximately 149 meters.

Earlier, the river gave power to numerous industry companies in Oslo. In the summer of 2008 Kunsthøgskolen i Oslo (The Oslo National Academy of the Arts) will move into this formerly industrial premises. The new campus will be one of the most spacious in Europe.

Akerselven is "Oslo’s green lung”; many parks and nature trails are to be found by its path, from Grønland to Maridalsvannet. A walk from along Akerselven from the rural Frysja down through the different parts of Oslo all the way down to the city centre is an amazing experience and a walk through the history of Oslo.^{[citation needed]}Salmon run and spawn in the upper part of the river.

Albert Nordengen (2 May 1923 in Våler, Østfold in Norway – 18 December 2004 in Oslo) was a Norwegian politician from the Conservative Party who became perhaps the most prominent, and best loved mayor in the history of the Norwegian capital.

He started his political career as a member of Oslo's city council in 1951. Through the years he also worked as a bank manager for Spareskillingssbanken (1964) and became group leader for the Conservative Party in the city council in 1968. In 1976 he became mayor, a position he held for fourteen years until 1990. Nordengen quickly became a much loved figure with the citizens of Oslo and despite being born in rural Østfold, he was a true Oslo patriot (even recording a version of the well-known Norwegian song "Akerselva", a tribute to the popular river that runs through the city). In October 2002 he received the King's Order of Merit in Gold for his services to Norwegian politics. In 1993 Nordengen received the Medal of St. Hallvard.

On 9 December 2004, after speaking at a gathering for veteran athletes, he collapsed in a parking lot due to a myocardial infarction. He never regained consciousness before dying nine days later at Diakonhjemmet Hospital.