The principle is the same as its coastal cousins: use the landscape itself as your primary defence, then reinforce only where nature falls short. Here, the spur is bounded on its north and south sides by steep scarps, the sharp, near-vertical faces of the slope dropping away sharply enough to discourage any casual approach. A berm, a narrow flat ledge or shelf cut into the hillside at the foot of each scarp, adds a further awkward step for anyone attempting to climb up from below.

Where the natural terrain runs out, on the western side where the spur meets higher ground and loses its defensive advantage, the builders compensated with an earthen bank and an external fosse, the fosse being a dug ditch placed on the outside of the bank to increase the effective height of the obstacle from an attacker's perspective. What survives of both is partial, reduced by centuries of agricultural activity and general weathering, but enough remains to read the original intention clearly. No entrance is visible at the surface today, which is not unusual for earthwork enclosures of this type; original causeways across fosses were often narrow and easily lost, or were deliberately removed when a site fell out of use. The fort has not been excavated or closely dated, so it sits in the broad category of later prehistoric or early medieval defensive enclosures that are common across Ireland without belonging firmly to any one period.