Chad–Nigeria border
The Chad–Nigeria border is 85 km (53 mi) in length and consists of a single diagonal line running NW to SE from the tripoint with Niger in the north to the tripoint with Cameroon in the south. Description This short boundary consists of a single straight line connecting Chad and Nigeria's tripoints with Niger and Cameroon. The entire boundary formerly lay entirely in Lake Chad, however given the dramatic decrease in the lake's size over the past several decades most of the boundary now run across land, swamp and intermittent exposed islands in the lake. History The border first emerged during the Scramble for Africa, a period of intense competition between European powers in the later 19th century for territory and influence in Africa. The process culminated in the Berlin Conference of 1884, in which the European nations concerned agreed upon their respective territorial claims and the rules of engagements going forward. As a result of this France gained control of the upper valley of the Niger River (roughly equivalent to the areas of modern Mali and Niger), and also the lands explored by Pierre Savorgnan de Brazza for France in Central Africa (roughly equivalent to modern Gabon and Congo-Brazzaville).