Formia dates back to pre-Roman population of the Aurunci and its history is also linked to the myth of Ulysses. When it was conquered by the Romans between the fifth and fourth centuries BC it became a thriving city for its port and the passage through it of the Via Appia.
Formia has been a tourist destination very appreciated by the Romans who built many villas like those of Mamurra, Maecenas and Cicero, who was murdered here in 43 BC.
With the Barbarian invasions citizens fled to the nearby hills.
It was invaded by the Goths (535 and 553), the Lombards and then the Saracens who destroyed completely the old town (846). On its ruins were then built villages of Mola and Castellone, which then gave rise to the present town.
During the second world war, it suffered heavy damage as it was near the Gustav line.