Castelforte is located on a natural terrace of limestone rock that dominates the plain of the Garigliano River to the Tyrrhenian Sea.
Castelforte is built on the ruins of the ancient city of Vescia destroyed by the Romans in 340 BC. The Roman baths Terme Vescinae were the site of the Suio Terme that were very popular in the Imperial era.
The Castrum Forte of the medieval village, basis of the current town, was instead formed around 1000 as a refuge for people seeking protection and the urban setting is typical of a military square. You notice the walls with towers, the gateway and the impressive tower, lookout point and communication with other fortifications. Another castle of Castelforte was in the hamlet of Suio that was owned by the monastery of Monte Cassino.
In these areas on Garigliano, in August 915, the Saracens were finally defeated by the League troops organised and commanded by Pope John X (who also attended to the Lombards and Byzantines). In 1079 it was definitely a possession of the Montecassino Signoria. From the thirteenth century came in the possessions of Counts of Aquila, the lords of Fondi and of Traetto. It later saw the passages of the Caetani family, the Colonna and Carafa.
During the Napoleonic invasion it rebelled against Napoleon and was conquered by the French and Polish troops under General Dombrowski.
During the Second World War it was destroyed in the fighting between the Germans and allies along the nearby Gustav line.