Borno State is a state in the North-East geopolitical zone of Nigeria, bordered by Yobe to the west, 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, being the only Nigerian state to border three foreign countries. Wikipedia