The enclosure measures roughly 27 metres across and is defined by a wide, low bank, about 6 metres broad, that varies in height depending on where you stand: at the southwest it still rises to 2.3 metres on the outside, giving a real sense of the original boundary, while the interior surface dips gently inward in a shallow, saucer-like profile. A slight gap in the bank at the northwest may represent the original entrance, the point through which people and animals once passed.

This is a rath, the earthwork form of a ringfort, the most common type of early medieval settlement monument in Ireland. Raths were typically the enclosed homesteads of farming families, dating broadly from around the sixth to the twelfth century, and they served as much as enclosures for livestock as defensible residences. What makes the Cartron example particularly interesting is what may lie beneath the surface. Within the enclosed area, there are indications of a souterrain, an underground stone-lined passage or chamber that was a common feature of ringfort settlements, used variously for storage, refuge, or both. Against the inner face of the bank at the north-northwest, a circular depression in the ground may be the ghost of a hut site, the compacted or subsided trace of a structure that once stood against the sheltering bank.