South Vietnam refers to an internationally recognized state which governed Vietnam south of the 17th parallel until 1975. Its capital was Saigon and its origin can be traced to the French colony of Cochinchina, which consisted of the southern third of Vietnam. This colony was reestablished in March 1946 and was proclaimed a republic in June. In 1949, the name was changed to State of Vietnam when former emperor Bảo Đại agreed to serve as head of state. The Bảo Đại government received international recognition in 1950. American support began in 1950 and gradually replaced French. Communists led by Hồ Chí Minh gained control of North Vietnam and set up a rival government based in Hanoi following the Geneva Conference in 1954. Bảo Đại was deposed in 1955 and a "Republic of Vietnam" led by Catholic leader Ngô Đình Diệm was proclaimed. After Diệm was deposed in a military coup in 1963, there was a series of short-lived military governments. General Nguyễn Văn Thiệu led the country from 1967 until 1975. The Vietnam War, in which the United States and South Vietnam fought North Vietnamese and Vietcong, began in 1958. Despite a peace treaty concluded in January 1973, fighting continued until April 1975, when North Vietnamese forces overran Saigon.
- 1946-47: Republic of Cochinchina
- 1947-48: Republic of South Vietnam
- 1948-49: Provisional Central Government of Vietnam
- 1949–55: State of Vietnam.
- 1955–75: the Republic of Vietnam.
- 1975–76: the Provisional Revolutionary Government of the Republic of South Vietnam.