Sudan-Central African Republic: periodic violent skirmishes persist among related pastoral populations along the border with the Central African Republic over water and grazing rights; Sudan closed its border with the Central African Republic in January 2022 due to security concerns

Sudan-Chad: Chad wants to be a helpful mediator in resolving the Darfur conflict, and in 2010 established a joint border monitoring force with Sudan, which has helped to reduce cross-border banditry and violence; however, since the August 2020 Juba Peace Agreement between the Sudanese Government and the Sudanese Revolutionary Front and the termination of the UN’s peacekeeping mission, UNAMID, at the end of 2020, violence continues to break out over land and water access

Sudan-Egypt: Sudan claims, but Egypt de facto administers, security and economic development of the Halaib region north of the 22nd parallel boundary

Sudan-Eritrea: none identified

Sudan-Ethiopia: civil unrest in eastern Sudan has hampered efforts to demarcate the porous boundary with Ethiopia; clashes continue between Sudan and Ethiopia over al-Fashaga, a fertile piece of land inhabited by Ethiopian farmers for years until the Sudanese army expelled them in December 2020, claiming the land belonged to Sudan based on colonial-era maps from over 100 years ago; in February, 2022, the two countries were discussing resuming talks over the border conflict; Ethiopia's construction of a large dam (the Grand Ethiopian Renaissance Dam) on the Blue Nile in northern Ethiopia since 2011 has become a focal point of relations with Egypt and Sudan; Sudan is concerned the dam will reduce the flow of water into the country; Ethiopia completed filling the dam in 2023

Sudan-Libya: none identified

Sudan-South Sudan: the 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; clashes continue in the oil-rich Abyei region; the United Nations Interim Security Force for Abyei (UNISFA) has been deployed since 2011, when South Sudan became independent; the United Nations Interim Security Force for Abyei (UNISFA) has condemned renewed clashes on 23 September 2022 between the Twik and Ngok Dinka communities taking place in Agok, 28 kilometres from Abyei town

Armenia-Azerbaijan: tensions existed for years over the break-away Nagorno-Karabakh region and the Armenian military occupation of surrounding lands in Azerbaijan; Azerbaijan seized part of the enclave during six weeks of fighting in 2020 and the remainder in a short conflict in September 2023; in October 2023, Baku and Yerevan began preliminary discussions on a peace treaty, the demarcation of borders, and full normalization of relations; nevertheless, concerns persist in Armenia that Azerbaijan could invade in order to force the establishment of a transit corridor to the exclave of Naxicvan (Nakhichevan)

Azerbaijan-Georgia: a joint boundary commission agrees on most of the alignment, leaving only small areas at certain crossing points in dispute; consequently, the two states have yet to agree on a delimitation or demarcation of their common boundary; one area of contention is where the international boundary should run through the 6th-13th Century David-Gareja monastery complex

Azerbaijan-Iran: in recent years, tensions between Azerbajian and Iran have risen in part because of warming ties between Azerbaijan and Israel, and Baku's claims that Tehran has backed Armenia over the disputed Nagorno-Karabakh enclave

Azerbaijan-Russia: Russia has complained of cross-border smuggling

Azerbaijan-Turkey: none identified; as of 2023, Turkey and Armenia were discussing normalizing relations

Caspian Sea (Maritime Boundary): Azerbaijan, Kazakhstan, and Russia ratified the Caspian seabed delimitation treaties based on equidistance, while Iran continues to insist on a one-fifth slice of the sea; bilateral talks continue with Turkmenistan on dividing the seabed and contested oilfields in the middle of the Caspian

local border forces struggle to control the illegal transit of goods and people across the porous, undemarcated Armenian, Azerbaijani, and Georgian borders