It is oval in shape, roughly six metres along its longer axis and four metres across, filled with loose rock and sunk to a depth of around half a metre. The leading interpretation is that this depression marks the blocked entrance to a souterrain, an underground passage or chamber of the kind commonly built in early medieval Ireland, typically used for storage, refuge, or concealment, and often associated with ringforts and cashels.

The cashel itself, a cashel being a stone-walled enclosure of roughly early medieval date, provides the immediate context. Souterrains were frequently constructed within such enclosures, and the in-filling of the entrance here, whether deliberate or gradual, has left this one sealed and largely unexamined. What lies beneath the rubble is unknown. The oval depression sits inside the cashel interior, meaning that whoever once used it would have moved between the protected space above ground and whatever chambers or passages extended below. The rock-filled state of the entrance suggests either a conscious decision to close it off at some point, or simply centuries of debris accumulating in a hollow that was no longer maintained.