Borno is a state in the North-East geopolitical zone of Nigeria. It is bordered by Yobe to the west, Gombe to the southwest, and Adamawa to the south while its eastern border forms part of the national border with Cameroon. Its northern border forms part of the national border with Niger and its northeastern border forms all of the national border with Chad. 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.