Horn of Africa Horn of Africa The Horn of Africa (, , , , ) (shortened to HOA; alternatively Somali Peninsula) is a peninsula in Northeast Africa. It juts hundreds of kilometers into the Arabian Sea and lies along the southern side of the Gulf of Aden. The area is the easternmost projection of the African continent. Referred to in ancient and medieval times as "Land of the Berbers" and "Habesha", the Horn of Africa denotes the region containing the countries of Djibouti, Eritrea, Ethiopia, and Somalia. It covers approximately 2,000,000 km (770,000 sq mi) and is inhabited by roughly 115 million people
Geology of Somalia and island arcs. In the Early Jurassic, the supercontinent Gondwana, which included Africa, began to break apart. The marine transgression of the Tethys Ocean flooded large parts of East Africa and Arabia and new sedimentary rock units were deposited. In the west of Somalia, the Cretaceous at the end of the Mesozoic brought crustal upwarping, which is preserved in the Yesomma Sandstone. Two major sedimentary basins began to form in Somalia during the Mesozoic, the Somali Coastal Basin and the Luuq-Mandera Basin, both filled with up to five kilometers of sedimentary rock. The basins formed due to the movements of