ATBARA(Bahr-el-Aswad, or Black River), the most northern affluent of the river Nile, N.E. Africa. It rises in Abyssinia to the N.W. of Lake Tsana, unites its waters with a number of other rivers which also rise in the Abyssinian highlands, and flows north-west Boo m. till its junction at Ed Darner with the Nile. The battle of the Atbara, fought near Nakheila, a place on the north bank of the river about 30 m. above Ed Darner, on the 8th of April 1898, between the khalifa's forces under Mahmud and Sir Herbert (afterwards Lord) Kitchener's Anglo-Egyptian army, resulted in the complete defeat of the Mandists and the capture of their leader, and paved the way for the decisive battle of Omdurman on the 2nd of September following (see EGYPT: Military Operations).