The mound itself is modest, roughly 3.5 by 4 metres and about 1.2 metres high, and so smothered in vegetation that it reads more as a natural hump in the ground than anything deliberately constructed. What lies beneath is a souterrain, an underground stone-lined passage or chamber typical of early medieval Ireland, where such structures were used variously for storage, refuge, or both. This one is 2.5 metres long, built in drystone, and completely blocked by collapse at both ends.

Despite being inaccessible, the structure offers one small concession to the curious. A low gap beneath the western roof slab allows a partial view into the interior, where the passage is roughly a metre wide and up to half a metre clear above the debris that covers the floor. The flagged roof sits only a quarter of a metre above the surrounding land surface, which gives some sense of how thoroughly the site has been absorbed back into the hillside. Around 1.5 metres from the western end, the roof drops by a further 0.2 metres, and it remains unclear whether this narrowing is simply a structural quirk or whether it signals the opening of a second passage or chamber beyond. That uncertainty is unlikely to be resolved without excavation. The site is known locally as An Lios, a name used in Irish for a ringfort or enclosed settlement, which may hint at a broader complex of which the souterrain was once a working part. The description was first recorded by J. Cuppage in the 1986 Dingle Peninsula archaeological survey of Corca Dhuibhne.

The mound sits on a slope with Brandon Bay visible 300 metres to the west, which means the location, whatever its original purpose, was not chosen without awareness of the landscape around it. The passage, sealed and silent, continues to sit there with at least one question still unanswered inside it.