The example at Carrickdexter in County Meath takes the same logic and applies it entirely inland, backing a roughly semicircular enclosure against a cliff face that rises to around thirty metres. The scarp defining the enclosure measures some fifty-two metres across its northeast to southwest axis, and within it sits a raised rectangular area, approximately twenty-four metres by nineteen metres, similarly defined by a scarp of its own. This inner platform, centred within the larger enclosure, is the kind of feature that might indicate a dwelling area or a space set apart from the rest of the fort's interior.

A promontory fort works by combining natural defensive terrain with constructed earthworks or stone walls to enclose a space. On a headland or coastal cliff, the drop itself discourages approach from one direction; the builders need only close off the remaining side. At Carrickdexter, the cliff substitutes for the sea, and the semicircular scarp completes the circuit. The possible entrance, as far as can be determined, was positioned at the west-southwest, which would have placed it away from the cliff edge and towards whatever approach route existed across the more open ground. The precise date of the fort's construction is not recorded, and promontory forts in Ireland span a wide range of periods, from the Bronze Age through to the early medieval, making firm attribution difficult without excavation.