These coastal fortifications were built by taking advantage of natural clifftop peninsulas, with defensive banks and ditches constructed across the landward approach to create an easily defendable position. The exact age of this particular fort remains uncertain, though similar sites across Ireland date from the Iron Age through to the early medieval period.

The fort at Carthage represents just one example of how Ireland's ancient inhabitants skilfully adapted the natural landscape for protection and control. Promontory forts are found all along Ireland's western seaboard, where dramatic cliffs and rocky headlands provided ready-made defensive positions. Communities would have used these sites not just for defence during times of conflict, but potentially as seasonal settlements, ceremonial spaces, or centres for controlling maritime trade routes.