毛德皇后地
In 1948, the newly created Norwegian Polar Institute was assigned the administration of Norwegian territories in the Arctic and Antarctic, including Queen Maud Land. Norway sent two major expeditions to the territory in the 1940s and 1950s, but its efforts declined after that. On 21 June 1957, Queen Maud Land became subject to Norwegian sovereignty as a dependency ("biland"), and the Antarctic Treaty officially came into force on 23 June 1961. Norwegian activity during the 1960s was limited to some minor co-expeditions with the United States, until it gradually picked up again following a larger expedition to western Queen Maud Land and the eastern Weddell Sea by the Norwegian Polar Institute in 1976–77.