Tanganyika was a territory in East Africa that came under German rule in the 1880s. Known as German East Africa, its rule transferred to the United Kingdom in 1916 in the midst of World War I. On 20 July 1922 the region became a United Nations Trust Territory.
For the next 30 years, it came under a dizzying array of administrations, including the Customs Union of the East African Protectorate, the East African Postal Union, the East African Posts and Telecommunications Administration, the East African High Commission, the East African Common Services Organisation, and the East African Community.
It was granted internal self-government on December 9, 1961. Later, on April 26, 1964 it merged with Zanzibar to become Tanzania.

This flag of the Tanganyika Territory is in the public domain.