South Sudan (ⁱ/ˌsaʊθ suːˈdæn/ or /suːˈdɑːn/), officially the Republic of South Sudan, is a landlocked country in the east-central African region of northeastern Africa. It is also part of the North Africa UN subregion. Its current capital is Juba, which is also its largest city; the capital city is planned to be moved 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. South Sudan includes the vast swamp region of the Sudd formed by the White Nile, locally called the Bahr al Jabal.

The modern states of South Sudan and Sudan were part of Egypt under the Muhammad Ali Dynasty, later being 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.

Sudan (ⁱ/suːˈdæn/ or /suːˈdɑːn/;Arabic: السودان‎, as-Sūdān), officially the Republic of the Sudan (Arabic: جمهورية السودان‎, Jumhūrīyat as-Sūdān), sometimes called North Sudan, is an Arab state in North Africa (sometimes also considered to be part of the Middle East). It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the southwest, Chad to the west, and Libya to the northwest. The population of Sudan is a combination of indigenous inhabitants of Nile Valley, and descendants of migrants from the Arabian Peninsula. Due to the process of Arabisation common throughout the rest of the Arab World, today Arab culture predominates in Sudan. The majority of the population of Sudan adheres to Islam. The Nile divides the country between east and west sides.

The people of Sudan have a long history extending from antiquity which is intertwined with the history of Egypt. Sudan suffered seventeen years of civil war during the First Sudanese Civil War (1955–1972) followed by ethnic, religious and economic conflicts between the Muslim Arab northern Sudanese and the mostly animist and Christian Nilotes of Southern Sudan. This led to the Second Sudanese Civil War in 1983. Because of continuing political and military struggles, Sudan was seized in a bloodless coup d'état by colonel Omar al-Bashir in 1989, who thereafter proclaimed himself President of Sudan. The civil war ended with the signing of a Comprehensive Peace Agreement which granted autonomy to what was then the southern region of the country. Following a referendum held in January 2011, South Sudan seceded on 9 July 2011 with the consent of Sudan's President al-Bashir.

Riek Machar Teny Dhurgon (born 1953), is the first vice-president of the independent Republic of South Sudan.

Riek Machar obtained a PhD in mechanical engineering in 1984 and then joined the rebel Sudan People's Liberation Movement/Army (SPLM/A) during the Second Sudanese Civil War (1983–2005). Riek fell out with the SPLM/A leader John Garang in 1991 and formed a splinter group, the SPLM/A-Nasir. In 1997 Riek made a treaty with the Government of Sudan and become head of the government-backed South Sudan Defense Force (SSDF). In 2000 he left the SSDF and formed a new militia, the Sudan People's Democratic Forces (SPDF), and in 2002 rejoined the SPLA as a senior commander. After the death of John Garang in July 2005, Riek Machar became vice-president of the autonomous Southern Sudan. He became vice-president of South Sudan on 9 July 2011 when the country became independent.

Riek Machar Teny Dhurgon was born in Leer, Unity State in 1953, the 26th son of the chief of both Ayod and Leer. He was brought up as a member of the Presbyterian church. Riek belongs to the Dok section of the Nuer people. He trained as an Engineer at Khartoum University, and obtained a PhD in Philosophy and strategic planning from the University of Bradford in 1984.