South Sudan vs. Ethiopia

South Sudan-Sudan boundary represents 1 January 1956 alignment, final alignment pending negotiations and demarcation; final sovereignty status of Abyei Area pending negotiations between South Sudan and Sudan; periodic violent skirmishes with South Sudanese residents over water and grazing rights persist among related pastoral populations along the border with the Central African Republic; the boundary that separates Kenya and South Sudan's sovereignty is unclear in the "Ilemi Triangle," which Kenya has administered since colonial times

Eritrea and Ethiopia agreed to abide by the 2002 Eritrea-Ethiopia Boundary Commission's (EEBC) delimitation decision, but neither party responded to the revised line detailed in the November 2006 EEBC Demarcation Statement; the undemarcated former British administrative line has little meaning as a political separation to rival clans within Ethiopia's Ogaden and southern Somalia's Oromo region; Ethiopian forces invaded southern Somalia and routed Islamist courts from Mogadishu in January 2007; "Somaliland" secessionists provide port facilities in Berbera and trade ties to landlocked Ethiopia; civil unrest in eastern Sudan has hampered efforts to demarcate the porous boundary with Ethiopia; Ethiopia's construction of a large dam (the Grand Ethiopian Renaissance Dam) on the Blue Nile since 2011 has become a focal point of relations with Egypt and Sudan; as of 2020, four years of three-way talks between the three capitals over operating the dam and filling its reservoir had made little progress; Ethiopia began filling the dam in July 2020