Ullernåsen is a hill and residential neighborhood in the Ullern borough of western Oslo, rising to about 201 meters above sea level. The area was historically part of the Ullern estates and remained mostly undeveloped until the early 20th century, when villa plots began to appear. After World War II, larger apartment buildings were added, giving the district a mix of single-family homes and low-rise blocks. Today, Ullernåsen is known as a quiet, green, and affluent neighborhood with good views over the city and easy access to nearby parks, schools, and transport connections.