South Sudan (,saʊθ_suːˈdæn or suːˈdɑːn), officially the Republic of South Sudan and previously known as Southern Sudan, is a landlocked country in east-central Africa that is part of the United Nations subregion of Eastern Africa. Its current capital is Juba, which is also its largest city. The capital city is planned to be changed to the more centrally located Ramciel in the future. South Sudan is bordered by Ethiopia to the east, Kenya to the southeast, Uganda to the south, the Democratic Republic of the Congo to the southwest, the Central African Republic to the west and Sudan to the north. It includes the vast swamp region of the Sudd, formed by the White Nile and known locally as the Bahr al Jabal.

The territories of modern South Sudan and Sudan were part of Egypt under the Muhammad Ali Dynasty, and later governed as an Anglo-Egyptian condominium until Sudanese independence was achieved in 1956. Following the First Sudanese Civil War, the Southern Sudan Autonomous Region was formed in 1972 and lasted until 1983. A second Sudanese civil war soon developed and ended with the Comprehensive Peace Agreement of 2005. Later that year, southern autonomy was restored when an Autonomous Government of Southern Sudan was formed.

South Sudan became an independent state on 9 July 2011, following a referendum that passed with 98.83% of the vote. It is a United Nations member state, a member state of the African Union, and a member state of the Intergovernmental Authority on Development. In July 2012, South Sudan signed the Geneva Conventions.