The Horn of Africa (alternatively Northeast Africa, and sometimes Somali Peninsula) is a peninsula of 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.

It indeed resembles in outline the horn of an animal perhaps especially, the horns of the Black Rhinoceros, whose historic range includes parts of Ethiopia.

Its orientation relative to the Equator approximates that of either rhino horn relative to the ground.  The angle between its northern and southeastern coasts approximates that at the tip of the rhino's upper horn. The concavity of its northern coast, and convexity of its southern, echo similar curvatures on the rhino's lower horn.

The term also refers to the greater region containing the countries of Djibouti, Ethiopia,Eritrea and Somalia. As such, it covers approximately 2,000,000 km≤ and is inhabited by about 86.5 million people. Sudan and Kenya are sometimes included as well.

Greater Somalia is a nationalist goal to create a unified Somali state in the Horn of Africa, in the former and present states referred to by the five points of the star in the national flag of Somalia since that country's independence: the former British and Italian colonies of present Somalia, the former French Somaliland now Djibouti), the Ogaden in Ethiopia, and the North Eastern province in Kenya.

The Horn of Africa is a region continuously in crisis. Ethiopia occupies a predominant position in the Horn because of its demographic importance: about 85% of the area's population live in this country. Yet Ethiopia's history is largely marked by conflicts between Muslims and Christians for resources and living space, as well as between nationalism and Marxism-Leninism.  (Source: http://en.wikipedia.org/wiki/Horn_of_Africa)