A souterrain, which is a man-made underground chamber or tunnel typically associated with early medieval settlement in Ireland, was discovered inside the remains of a cashel, a type of stone-walled ringfort enclosure, and then effectively vanished from record until it was rediscovered in 1976, at which point it was described as having been "covered in". Today, there is no visible trace of it anywhere within the cashel. The most tangible evidence that it ever existed at all now sits in a display case in Dublin.

That evidence is a sword, recovered from the souterrain and now held in the National Museum of Ireland, as noted by Donnelly in 1994. The cashel in which the souterrain sits carries the site reference LI020-004001-, and the souterrain itself is protected by a preservation order issued under the National Monuments Acts 1930 to 2014, with order number 4/1977. The fact that a preservation order was deemed necessary for a site with no surface expression is, in itself, a quiet indication of how seriously the archaeology beneath the ground is regarded, even when there is nothing left to see.

For a visitor, the honest situation is this: the souterrain is underground and covered in, and the cashel enclosure above it offers no obvious physical marker of what lies beneath. The sword that was found here, the most compelling object associated with the site, is accessible not in Limerick but in Dublin, at the National Museum of Ireland on Kildare Street. Anyone with a serious interest in the monument would do well to consult the National Monuments Service records or the relevant Sites and Monuments Record entry before visiting, simply to orient themselves within the landscape of what remains. The cashel itself, as a scheduled monument under legal protection, should not be disturbed or excavated without proper authorisation.