Chad–Niger border

A line inside the French empire

The border first divided two French colonial federations: French West Africa, which included Niger, and French Equatorial Africa, which included Chad. France set and changed it by administrative decisions, and it became an international border only when both countries became independent in 1960.^[1]

French forces reached the area from three directions. In 1899–1900 expeditions marched south from Algeria, east from the Niger and north from the French Congo, and met at Kousseri, south of Lake Chad, on 21 April 1900, linking France’s African possessions.^[1] Niger became a military territory in 1901 and a colony in 1922; Chad was made a separate territory in 1914 and a colony in 1920.^[1]

Moving the Tibesti

In the south, a convention between the military commanders of Chad and Niger, approved on 11 February 1912, ran the line from the British border in Lake Chad northeast past the wells of Molo, Fayenga and Firkachi, leaving the line undecided north of 16°N.^[1]

Early maps put the Tibesti mountains partly in Niger. On 18 March 1931 French Memorandum No. 2268 officially transferred the Tibesti from Niger to Chad, and the line was redrawn to the west of the mountains.^[1] A French commission worked north of Lake Chad in 1939, and an agreement between the governors of Chad and Niger in 1957 appears to be the basis of the line between Molo and Siltou.^[1]

In 1966 the US Geographer noted that maps had shown the border in many different places since 1900, owing to poor knowledge of the land and broad readings of administrative orders, and that no pillars were known to mark it.^[1]

“Finally, by the means of this solution, the administrative boundary of the Territory eastward would be undecided north of the 16th degree of latitude.”^[1]

Lake Chad

The southern end lies in Lake Chad, whose tripoint with Nigeria was fixed by Anglo-French conventions of 1898, 1904 and 1906. The border crosses about 46 miles (74 km) of the shallow freshwater lake, whose area in 1966 ranged between 4,000 and 8,000 square miles between low and high water, leaving its shoreline often undefined.^[1]

North of the lake, sand and gravel stretch for about 500 miles, including dunes such as the Grand Erg de Bilma, before the rocky plateau of the Massif d’Afafi west of the Tibesti.^[1]