The passage is sealed, inaccessible, known only by the line of flat roof lintels that break the surface in a neat northwest to southeast alignment. Where gaps appear between those lintels, the drystone walling of the tunnel below becomes briefly visible, a glimpse into a carefully constructed void that has outlasted whatever purpose it once served.

A souterrain is an artificially constructed underground passage or chamber, typically built during the early medieval period in Ireland, usually associated with nearby settlement. They are generally thought to have served as places of storage, refuge, or both. This one sits within the northwest sector of a cashel, a type of early Irish stone fort enclosed by a circular drystone wall, suggesting the two structures were part of the same early medieval complex. The souterrain extends from roughly the centre of the cashel's interior outward to the cashel wall at the northwest, a trajectory that may have offered a concealed exit point. To the southeast of the passage lies a children's burial ground, a cillín, where unbaptised infants were traditionally interred in unconsecrated ground, often at the margins of older, pre-Christian monuments. The proximity of these three features, the cashel, the souterrain, and the burial ground, layers the site with centuries of different kinds of use and meaning.

The lintels are visible at ground level, which means the passage announces itself to anyone who knows what to look for, even if its interior remains closed off. The drystone construction glimpsed in the gaps between stones gives a sense of the care and skill that went into building something designed, in part, to be unseen.