Bir Tawil
In 1899, the Anglo-Egyptian Condominium Agreement for Sudan set the border between the territories at the 22nd parallel. At that time, the United Kingdom ruled the area. In 1902 the UK drew a separate "administrative boundary". Using this boundary,  a triangle of land north of the parallel was placed under Sudanese administration. It was because its inhabitants were closer to Khartoum than Cairo, both geographically and culturally. The area was ruled by the British Governor in Khartoum.