Not collapsed, not eroded, but deliberately filled in, leaving no trace on the surface whatsoever. The only evidence that it ever existed comes from a single local man who recalled crawling through it as a child, and from that memory alone, the site was recorded.

A souterrain is an underground stone-built passage or chamber, typically associated with early medieval settlement in Ireland, often interpreted as a place of refuge, cool storage, or escape route. This one was modest by any measure: roughly 1.8 metres long, 0.9 metres wide, and 1.2 metres high, just large enough for a small person to move through on hands and knees. It sat at the southern end of a hummock in low-lying grassland, and when investigators documented it in 1989, it was already partially blocked with stones. It was subsequently filled entirely. Around 110 metres to the south-south-east lies a rath, a circular earthwork enclosure of the kind commonly built as a farmstead in early medieval Ireland, and the two features together suggest a landscape that was once organised and inhabited in ways now almost entirely invisible.

There is nothing to see here now. The hummock remains, but the entrance is gone and the chamber beneath it is sealed. What lingers is the particular strangeness of a site whose existence rests almost entirely on the recollection of one person, a child who once squeezed into the dark and came back out again.