Chad Basin British and French concluded an agreement to clarify the boundary between French West Africa and what would become Nigeria. A boundary was agreed along a line from Say on the Niger to Barruwa on Lake Chad, but leaving the Sokoto Caliphate in the British sphere. Parfait-Louis Monteil was given charge of an expedition to discover where this line actually ran. On 9 April 1892 he reached Kukawa on the shore of the lake. Over the next twenty years a large part of the Chad Basin was incorporated by treaty or by force into French West Africa. On 2 June 1909
Chad Basin the Wadai capital of Abéché was occupied by the French. The remainder of the basin was divided by the British in Nigeria who took Kano in 1903, and the Germans in Kameroun. The countries of the basin regained their independence between 1956 and 1962, retaining the colonial administrative boundaries. As of 2011, over 30 million people lived in the Chad Basin. The population is growing rapidly. Ethnic groups include Kanuri, Maba, Buduma, Hausa, Kanembu, Kotoko, Bagger, Haddad, Kuri, Fulani and Manga. The largest cities are Kano and Maiduguri in Nigeria, Maroua in Cameroon, N'Djamena in Chad and Diffa in Niger.