Osun State is a state in South West Nigeria. It was created in August 1991 from the old Oyo State. Its name was taken from the Osun River in the state.
The state is divided between the Nigerian lowland forests in most of the state and the drier Guinean forest–savanna mosaic in the north. The major geographical features are rivers including the River Osun which bisects the state's interior before forming much of the state's southwestern border with Oyo State and flowing south. Other important rivers are the Erinle and Oba rivers, both Osun tributaries which flow from the north before meeting the Osun along the southwestern border.
Among the state's nature are mona monkey, common kestrel, purple heron, and royal antelope populations along with some of Nigeria's last remaining Nigeria-Cameroon chimpanzee and African forest elephant populations in the heavily threatened forests along the southern borders with Ondo and Ogun states.
Osun State is primarily inhabited by the Yoruba people, mainly of the Ibolo, Ifẹ, Igbomina, Ijesha, and Oyo subgroups. Religiously, the majority of the state's population (~55%) are Christian with Muslim (mainly Sunni) and traditionalist (primarily Ìṣẹ̀ṣe) minorities at about 40% and 5%, respectively.
Economically, Osun State is largely based around agriculture, mainly of cocoa, cassava, millet, maize, and yam crops. Other key industries are services, especially in urban areas, along with artisanal mining and livestock herding.
Major motor parks in Lagos have buses that pass through Osun state.
Osun is home to several of Nigeria's most famous landmarks, including the campus of Obafemi Awolowo University, one of Nigeria's pre-eminent institutions of higher learning. The university is located in the ancient town of Ile-Ifẹ, an important early centre of political and religious development for Yoruba culture.
The Erin-ijesha Waterfalls, near Ilesa, are where the Owa Obokun the monarch of Ijeshaland is initiated and taken before he ascends the throne.
Ilobu, near Ifon Osun, is a big arts and crafts centre in Nigeria. These include metal crafts, weaving, painting and sculpturing, leather work, and the adire method of dyeing clothes.
Ọsun-Ọsogbo Grove, the shrine of the annual rites of the deity Osun and an important artistic centre just outside the city of Osogbo, was declared a World Heritage Site in 2005
Every year, adherents and non-adherents of Osun, one of the Orisa (the traditional deities of the Yoruba people), travel from all over the world to attend the annual Osun-Osogbo festival in Osogbo in August. Traditional festivities and invocations of the Osun goddess are held along the banks of the river bearing her name into which – according to Yoruba Oratory traditions – she transformed.