Inhabited since very ancient times (between 5000-3000 BC), l'Île-Rousse was in 1000 BC a small, prosperous town dependent on Tyre in Phoenicia, called Agilla.
In the 17th century, merchants from Santa-Reparata-di-Balagna established shops to trade by sea with the coastal villages of the Balagne, Nebbio, and the west of the Cap Corse.