After more than a half century of civil war, which began even before Sudan’s independence from the United Kingdom, South Sudan became a recognized, separate country in 2011. The international boundary between the two States is based on the provincial boundaries at the time of Sudan’s independence from the United Kingdom on 1 January 1956. Much of the modern international boundary remains disputed due to colonial territorial swaps made for administrative convenience and without much heed for the tribal and religious alliances that occurred between the peoples of northern and southern Sudan. Furthermore, many of the British instruments which defined the boundaries of the various provinces are vague and imprecise, leading to difficulties in establishing a modern delimitation.

The boundary separating South Sudan from Sudan extends for approximately 2,000 kilometers (1,240 miles) from the tripoint with the Central African Republic in the west to the tripoint with Ethiopia in the east. There are eight areas of dispute across the length of the boundary, the most famous of which is the disputed Abyei Area, which was defined by an international tribunal in 2009.

The border region between South Sudan and Sudan remains unstable and prone to violence, with clashes between the militaries of the two governments and between various local peoples. Seasonal migration occurs in the border region, which has complicated ideas of land ownership, rights, and sovereignty. Much of the frontier is considered agriculturally and economically valuable due to the presence of rich farmland and hydrocarbon reserves. Owing to the importance of the frontier area, neither country has been willing to compromise, and the de facto, disputed boundary lingers without much hope of bilateral resolution.