The Horn of Africa (alternatively Northeast Africa, and sometimes Somali Peninsula; shortened to HOA) is a peninsula in East Africa that juts for hundreds of kilometers into the Arabian Sea, and lies along the southern side of the Gulf of Aden. It is the easternmost projection of the African continent. Referred to in medieval times as Bilad al Barbar ("Land of the Berbers"),the Horn of Africa denotes the region containing the countries of Eritrea, Djibouti, Ethiopia and Somalia.As such, it covers approximately 2,000,000 km² (772,200 sq mi) and is inhabited by about 100.2 million people (Ethiopia: 75 million, Somalia: 10 million, Eritrea: 4.5 million, and Djibouti: 0.7 million). Regional studies on the Horn of Africa are carried out, among others, in the fields of Ethiopian Studies as well as Somali Studies.