The interior of this stone enclosure, roughly 17 metres across, is so densely packed with small stones that the fill reaches, and in places exceeds, the level of the outer wall-top. The inner wall-face is entirely invisible, buried beneath the accumulated rubble, and it remains genuinely unclear whether this is the result of centuries of collapse or whether the interior was always substantially raised above the surrounding ground level. A cashel is a type of stone-walled ringfort, built without mortar, and this one contains two drystone huts, a souterrain, and an ogham stone, all of them now half-consumed by the stony interior fill.

The ogham stone, which lies loose near the souterrain, carries an inscription that reads TOGITTACC MAQI SAGARET(TOS), a formula typical of early medieval commemorative stones, identifying a person by name and parentage. Ogham is an early Irish script in which letters are represented by notches and strokes cut along a central line, usually the edge of a standing stone. The stone was first recorded in 1855 by the Reverend James Goodman, and Goodman's family later reported that it had been found serving as the entrance lintel to the souterrain, which is a stone-lined underground passage, here aligned roughly south-west to north-east. Whether the stone was ever actually part of the souterrain entrance, or had simply come to rest nearby, became a matter of some dispute. Samuel Ferguson, writing in 1887, placed its origin in an adjoining killeen, a small unconsecrated burial ground typically used for unbaptised infants, but this account does not square with earlier testimonies. What is not disputed is the stone's later fate: it was smashed into three pieces in the 1880s, one fragment was lost, and the inscription as it now reads is pieced together from the two surviving fragments, each scholar who examined it before the break, including Du Noyer, Hitchcock, and Brash, having agreed on what the missing section said.

The souterrain itself adds a further layer of strangeness to the site. A single roofing slab is visible at the surface, and a gap beneath it allows limited access to the passage, though it is largely blocked by collapse. A large slab set into the outer cashel wall at the north-east is said locally to mark the souterrain's exterior entrance, but that gap has since been sealed. The slab sits at least 0.8 metres below the level of the interior roofing slabs, which means the passage must have sloped downward toward the outside, an unusual feature that suggests the whole structure was designed to be entered from beyond the cashel wall rather than from within it.