Egypt attempted to colonize the region of southern Sudan by establishing the province of Equatoria in the 1870s. Islamic Mahdist revolutionaries overran the region in 1885, but in 1898 a British force was able to overthrow the Mahdist regime. An Anglo-Egyptian Sudan was established the following year with Equatoria being the southernmost of its eight provinces. The isolated region was largely left to itself over the following decades, but Christian missionaries converted much of the population and facilitated the spread of English. When Sudan gained its independence in 1956, it was with the understanding that the southerners would be able to participate fully in the political system. When the Arab Khartoum government reneged on its promises, a mutiny began that led to two prolonged periods of conflict (1955-1972 and 1983-2005) in which perhaps 2.5 million people died - mostly civilians - due to starvation and drought. Ongoing peace talks finally resulted in a Comprehensive Peace Agreement, signed in January 2005. As part of this agreement, the south was granted a six-year period of autonomy to be followed by a referendum on final status. The result of this referendum, held in January 2011, was a vote of 98% in favor of secession.
Since independence on 9 July 2011, South Sudan has struggled with good governance and nation building and has attempted to control opposition forces operating in its territory. Economic conditions have deteriorated since January 2012 when the government decided to shut down oil production following bilateral disagreements with Sudan. In December 2013, conflict between government and opposition forces killed tens of thousands and led to a dire humanitarian crisis with millions of South Sudanese displaced and food insecure. The warring parties signed a peace agreement in August 2015 that created a transitional government of national unity in April 2016. However, in July 2016, fighting broke out in Juba between the two principal signatories, plunging the country back into conflict.
Maps and information from The World Factbook.