Whatever its origins, this souterrain at Cloghardeen spent well over a century unrecorded by the cartographers who mapped almost everything else around it.

A souterrain is a man-made underground structure, typically associated with early medieval settlement in Ireland, built from stone and used variously for storage, refuge, or concealment. This one was brought partially to light when the landowner at Cloghardeen House uncovered a section of it. Its construction follows a method recognisable elsewhere across the country: dry-stone walling rising to a corbelled roof, where successive courses of stone are laid so that each slightly overhangs the one below, eventually closing the space without mortar or a true arch. The original lintel stone, which would have covered the entrance, is now gone, and the exposed portion is protected by nothing more than a metal sheet. At the time of inspection, the interior was waterlogged. There is no visible trace above ground of any enclosure that might once have surrounded it, which makes placing it within a wider settlement pattern difficult. The land drops away to the River Suir roughly a hundred metres to the west, a proximity that may help explain why water collects inside.