The Horn of Africa (HoA), also known as the Somali Peninsula, is a large peninsula and geopolitical region in East Africa. Located on the easternmost part of the African mainland, it is the fourth largest peninsula in the world. It is composed of Ethiopia, Eritrea, Somalia and Djibouti; broader definitions also include parts or all of Kenya, Sudan, South Sudan, and Uganda. The term Greater Horn Region (GHR) can additionally include Burundi, Rwanda, and Tanzania. It lies along the southern boundary of the Red Sea and extends hundreds of kilometres into the Guardafui Channel, Gulf of Aden, and Indian Ocean and shares a maritime border with the Arabian Peninsula of Western Asia.