DR Congo–South Sudan border

Leopold’s lease

In 1885 the new Congo Free State of King Leopold II declared limits that reached the 4th parallel north. An agreement with Britain on 12 May 1894 fixed the Free State’s edge along the watershed between the Congo and the Nile, and in return for recognising Britain’s sphere in Uganda, Leopold was leased large territories on the Nile side, mostly the Bahr al Ghazal.^[1]

Because of French interests in the region, Leopold occupied only the Lado Enclave, named after the river port of Lado on the Bahr al Jabal about 10 miles north of Juba, and the Mahagi strip. The rest of the lease was annulled in 1906, and after an Anglo-Belgian agreement of 14 May 1910 the enclave was handed to the Anglo-Egyptian Sudan on 16 June 1910.^[1]

“The lease shall remain in force during the reign of His Majesty Leopold II, Sovereign of the Independent Congo State.”^[1]

The watershed line

In 1914 the southern part of the former enclave went to Uganda as its West Nile District, and the Sudan–Uganda line fixed that year set the eastern tripoint. The western tripoint was marked in 1924 with a large monument of stones. Between them the border follows the Congo–Nile divide.^[1]

The Belgian Congo became independent on 30 June 1960 and Sudan on 1 January 1956. In 1978 the line was still the Sudan–Zaire boundary; it became the border with South Sudan when that country became independent.^[1]