A roughly circular earthen bank, measuring about 38 metres north to south and 36 metres east to west, encloses the site, and the difference between its interior and exterior heights tells you something about the effort that went into it: from inside, the bank rises about 1.1 metres, but from the outside it presents a face of 3.2 metres, much of that effect achieved by the fosse, or defensive ditch, that runs along the eastern and southern sides and survives in a shorter section to the west as well. A ringfort of this kind, sometimes called a rath, was the typical enclosed farmstead of early medieval Ireland, home to a farming family of some local standing, and the earthworks here are legible enough to trace that original purpose without much imagination.

The eastern side of the bank has a gap about 3.5 metres wide that would have served as the entrance. It is now blocked by boulders, but beyond it a slight causeway crossing the fosse and a short passageway survive, giving a sense of how a visitor or inhabitant would once have moved in and out of the enclosure. Inside, the ground slopes gently down towards the north and is crossed by the faint corrugations of old cultivation ridges, the traces of strip farming within the enclosed space. In the north-western quadrant there are signs of a possible souterrain, an underground stone-lined passage or chamber that was a common feature of ringforts, used variously for storage, refuge, or both. To the north of the entrance causeway, heavily overgrown remains suggest a rectangular structure of uncertain date and function. What makes the Carrigboy rath particularly interesting as a landscape feature is that another ringfort sits roughly 300 metres to the east, a reminder that these enclosures were rarely solitary; they existed within farming communities, and the land between them would once have been worked and shared.