Ilaro was founded in the middle of the 17th century, about 1640 – 1650 AD. The ancient town was founded by a brave hunter and farmer name ARO from Oyo Ile. Aro fled Oyo in the wake of violent disturbances which often accompanied the demise of an Alafin in those days.

Aro travelled south-west and settled at a place known today as Ilaro, an abbraviation of ILU-ARO. Not long after, the settlement was faced with serious threats of invasion from the notorious Dahomean Army. Aro therefore sent messages to princes and warriors in Oyo to join him in providing strong defense for the fertile land.

One of the Princes who answered the call was ORONNA, who afterwards distinguished himself in battles and became the generalissimo in defending the settlement by demolishing the Dahomeans who were a scourge in the area.

Oronna’s miltary prowess was so great. Whenever there was any threat of war, Oronna would emerge with his army and repel the invadars with little or no casualities from his army. He became an acknowledged hero of his people, as no enemy dared challenge Ilaro to war, hence the own knew so much peace.

Oronna pledged that even in death, his people should call on him to defend Ilaro. He disappeared into the earth, leaving a tail of a long chain tied to his waist. The pointh of his disappearance is now called ORONNA SHRINE, now a tourist destination in Ogun State.