Region demarcated along ethnic lines and Ethiopia's largest in area.
The predominant ethnic group are the Somalis at almost 99% of the population, and the language spoken is Somali.
Area had been sought after by neighbor Somalia which invaded Ethiopia, igniting the Ogaden War (July 1977 to March 1978). Ethiopia was cornered and all appeared lost until a timely 16,000+ troop intervention from Cuba, a further two brigades from South Yemen and 1,500 Soviet 'advisors' turned the tide. This wiped out a third of the Somali army. Somalia subsequently gave up its claim to the area [Link]
Desires for a 'Greater Somalia' still persist, and the federal government has had its hands full trying to pacify the region, especially against the separatist Ogaden National Liberation Front.