Borettslaget Oslo Havebyselskap, also known as Ullevål hageby, is a residential area consisting of 119 buildings with a total of 652 apartments. The buildings were constructed between 1918 and 1926 and are known for their harmonious whole and character worthy of preservation. The area is registered on Byantikvaren's yellow list, which indicates that it has national conservation value.
The housing association has a history of collective ownership that goes back to before the introduction of the Act on housing associations. The design of the garden city is inspired by garden cities in Germany and England, and there is an active effort to preserve both culture and the environment in the area. This makes Ullevål hageby a unique and valuable residential environment in Oslo.