Onil does not constitute like town until entered good the Average Age. It is now when are testimonies written. Their near earth and houses at the end of Biar, comprised of the region of the Foia the capital of which is Castalla.

It is possible to emphasize in Onil, the Fen, that formerly was a pantanal and that dissected in century XVIII has been the testimony of the day to prehistoric day and later destined to the culture of vegetables, arriving to be in its time an authentic orchard of the Kingdom.

Onil that in century XVIII was integrated to the industrial movement, got to be one of the main populations with textile industrial activity in the Kingdom of Valencia, policy that left to return to agriculture like other towns.