The Oṣun River, Yoruba: Odò Ọ̀ṣun, is a river of Yorubaland that rises in Ekiti State and flows westwards into Osun State before turning southwestwards at its confluence with the Erinle River near the town of Ede and then heading south at the Asejire reservoir flowing though the rest of the state and Ogun State in Southwestern Nigeria before eventually discharging into the Lekki Lagoon and the Atlantic at the Gulf of Guinea.

Ekiti State is a state in southwestern Nigeria, bordered to the North by Kwara State for 61 km, to the Northeast by Kogi State for 92 km, to the South and Southeast by Ondo State, and to the West by Osun State for 84 km. Named for the Ekiti people—the Yoruba subgroup that make up the majority of the state's population—Ekiti State was carved out from a part of Ondo State in 1996 and has its capital as the city of Ado-Ekiti.