BORKU or BORGU, a region of Central Africa between 17° and 19° N. and 18° and 21° E., an extension of the Chad depression (16o metres, altitude) forming part of the transi tional zone between the Sahara and the fertile central Sudan. Bounded east by the Ennedi and north by the Tibesti mountains, it is in great measure occupied by lesser hills belonging to the same system, merging south and east into the plains of Wadai and Darfur. South-west, in the direction of Lake Chad, is the Bodele basin. The country drains to the lake, but the numerous khors mostly contain water for brief periods only. A considerable part of the soil is light sand drifted about by the wind. Oases produce dates and barley. The northern valleys are inhabited by a settled population of Tibbu stock, known as the Daza, and by colonies of negroes; the others are mainly visited by nomad Berbers, the dominant Arab Ouled Sliman, and the Senussi, also Arabs. The inhabitants own large numbers of goats and asses.
Borku is also called Borgu, but must not be confounded with the Borgu (q.v.) west of the Niger. It was lately opened up; and was described by Gustav Nachtigal in Sahara and Sudan (Berlin, 1879-89). An Anglo-French agreement (1899) gave Borku to France; it was under the Senussi but the French entered in 1907, retiring again afterwards. Borku now forms part of the French territory of Chad.