A souterrain, one of the dry-stone underground passages or chambers built in early medieval Ireland, typically for storage or refuge, once lay here, just 110 metres from the Royal Canal and a short distance south of the village of Ballynacarrigy. By the time anyone thought to record it formally, it was already gone.

When Kevin O'Brien visited in February 1985, the souterrain was already described as destroyed, and no further details were captured at the time. What fills the gap is aerial photography. A series of photographs taken by Cambridge University between 1966 and 1970 shows this field containing numerous earthworks, several of which were already fading into the ground. One photograph from 1966 shows a sub-circular enclosure with particular clarity, and it is within this enclosure that the souterrain is thought to have been located. Such enclosures are a common feature around early medieval settlement sites in Ireland, where a ringfort or similar structure would have enclosed a household, with a souterrain beneath providing cool storage or a place of concealment. By the time a Digital Globe aerial photograph was taken in November 2011, the enclosure itself was only partially visible, and the earthworks had diminished further still. The site now sits quietly on the townland boundary with Ballynacarrigy Old, its outline dissolving incrementally back into the landscape.