Borno State is a state in the North-East geopolitical zone of Nigeria. It is bordered by Yobe to the west for about 421 km, Gombe to the southwest for 93 km, and Adamawa to the south while its eastern border forms part of the national border with Cameroon for about 426 km. Its northern border forms part of the national border with Niger for about 223 km, mostly across the Komadougou-Yobe River, and its northeastern border forms all of the national border with Chad for 85 km ,.It is the only Nigerian state to border up to three countries. It takes its name from the historic emirate of Borno, with the emirate's old capital of Maiduguri serving as the capital city of Borno State. The state was formed in 1976 when the former North-Eastern State was broken up. It originally included the area that is now Yobe State, which became a distinct state in 1991.