The 1838 Ordnance Survey six-inch edition marked the spot simply as "Cave", which was either a piece of local memory preserved in cartographic amber, or a mapmaker's educated guess. When archaeologists came to inspect it in December 1982, they found nothing at all above ground. The site gave nothing away.

It took a mechanical digger, arriving in March 2000 to prepare ground for a septic tank, to settle the matter. Two of the structure's roof lintels were displaced during the work, and through that accidental opening it became possible to crawl inside and see what had been quietly sitting there all along. A souterrain, the term used for an underground stone-built passage typically associated with early medieval settlement, ran for just under eight metres on an east-north-west to west-south-west axis. The passage was narrow, under a metre wide, but tall enough in places to stand at 1.67 metres. Its walls were built from coursed limestone boulders and the ceiling was formed by ten lintels, eight of which were still in their original positions. Three wall cupboards were cut into the stone, two in the north wall and one in the south, small recesses whose purpose might have been storage or concealment. The floor was covered in mud and loose stone. The souterrain sits in association with what may be a rath, the ringfort-style enclosure that would have been the focus of a farming settlement during the early medieval period, suggesting this underground passage once served whoever lived within that enclosure, perhaps as a place to store goods, or as a bolt-hole in times of trouble.

The structure lies in pastureland, and the manner of its rediscovery is a reminder of how much survives beneath ordinary agricultural ground in Ireland, invisible even to close inspection, waiting on the particular bad luck of a digger bucket.