Oromia (ኦሮሚያ) (Oromiyaa) is a regional state in Ethiopia and the homeland of the Oromo people. The capital of Oromia is Addis Ababa.
It is bordered by the Somali Region to the east; the Amhara Region, the Afar Region and the Benishangul-Gumuz Region to the north; Dire Dawa to the northeast; the South Sudanese state of Upper Nile, Gambela Region, South West Ethiopia Region, Southern Nations, Nationalities, and Peoples' Region and Sidama Region to the west; the Eastern Province of Kenya to the south; as well as Addis Ababa as an enclave surrounded by a Special Zone in its centre and the Harari Region as an enclave surrounded by East Hararghe in its east.
In August 2013, the Ethiopian Central Statistics Agency projected the 2022 population of Oromia as 35,467,001; making it the largest regional state by population. It is also the largest regional state covering Oromia is the world's 42nd most populous subnational entity, and the most populous subnational entity in Africa.
The Oromo people are one of the oldest Cushitic peoples inhabiting the Horn of Africa, as there is still no reliable estimate of the history of their settlement in the region. However, many indications suggest that they have been living in the north of Kenya and south-east Ethiopia for more than 7000 years until the great expansion in 1520 when tn they expanded to the south-west and some areas in the north.
The Oromo and their country Oromia (biyyi Oromiyaa) remained independent until the last quarter of the 19th century, when they lost their sovereignty. From 1881 to 1886, Emperor Menelik II conducted several unsuccessful invasion campaigns against their territory. The Arsi Oromo demonstrated fierce resistance against this Abyssinian conquest, putting up stiff opposition against an enemy equipped with modern European firearms. They were ultimately defeated in 1886.
In the 1940s some Arsi Oromo together with people from Bale province joined the Harari Kulub movement, an affiliate of the Somali Youth League that opposed Amhara Christian domination of Hararghe.