South Vietnam was a country. It existed from 1955 to 1976. It was in the south of what is now Vietnam. The country was south of the local Demilitarized Zone, and North Vietnam was to the north of it.
As the Republic of Vietnam, it was ruled first by the unpopular Ngo Dinh Diem (Vietnamese: Ngô Đình Diệm) and then by a military dictatorship.
The division of Vietnam took place during the Geneva Conference of 1954. In 1975, North Vietnam took over this country and renamed its largest city, Saigon, to Ho Chi Minh City.