Akershus is a traditional region and current electoral district in Norway, with Oslo as its main city and traditional capital. It is named after the Akershus Fortress in Oslo. From the middle ages to 1919, Akershus was a fief and main county that included most of Eastern Norway, and from the 17th century until 2020, Akershus also had a more narrow meaning as a (sub) county that included most of the Greater Oslo Region.