United Nations Trust Territories were the successors of the League of Nations mandates and came into being when the League of Nations ceased to exist in 1946. All of the trust territories were administered through the UN Trusteeship Council. The one territory not turned over was South West Africa, which South Africa insisted remained under the League of Nations Mandate, and which eventually gained independence in 1990 as Namibia. The main objection was that the trust territory guidelines required that the lands be prepared for independence and majority rule. Trust territories (and administering powers) were:

• Cameroon (France) and Cameroons (United Kingdom) - The French portion was granted independence as the Republic of Cameroon in 1960. The somewhat smaller British portion had been administered in two parts (Northern Cameroons and Southern Cameroons). Following a plebiscite, Northern Cameroons became part of Nigeria in May 1961 and Southern Cameroons joined the Republic of Cameroon in October 1961.
• Nauru (Australia) - Granted independence in 1968.
• New Guinea (Australia) - The north-eastern section of this island had been a League of Nations mandate. The south-eastern section had been Australian before World War I. After World War II, the two were combined into a unified trust territory which was granted independence as Papua New Guinea in 1975. The western half of the island, formerly Dutch and now part of Indonesia, was never part of the trust territory.
• Trust Territory of the Pacific Islands (U.S.) - Split into The Republic of the Marshall Islands (1979), The Federated States of Micronesia (1979), The Commonwealth of the Northern Mariana Islands (1978), and The Republic of Palau (1981). With the exception of The Northern Mariana Islands, which is a commonwealth, they are all Associated States of the U.S.
• Ruanda-Urundi (Belgium) - Gained independence in 1962 as the countries of Rwanda and Burundi.
• Somalia (Italy) - Granted independence, and merged with former British Somaliland, in 1960.
• Tanganyika (United Kingdom) - Became independent in 1961. Merged with Zanzibar in 1964 to form Tanzania.
• Togoland (France and United Kingdom) - The French portion became independent as Togo in 1960. The much smaller British portion was merged in 1946 with the British colony of the Gold Coast, which was granted independence as Ghana in 1957.
• Western Samoa (New Zealand) - Granted independence in 1962, now known simply as Samoa.

References

United Nations | Imperialism | League of Nations Mandates

Territoris fideïcomissaris | Treuhandgebiet | Protectorado das Nações Unidas