The site is known locally as Listonavally, or Lios Tón an Bhaile in Irish, and what survives above ground is already quietly odd: a circular enclosure roughly 26 metres across, its interior raised up to 1.5 metres above the surrounding field level, its outline preserved partly by a barely perceptible bank, partly by a natural scarp, and partly by a modern field wall that happened to follow the same curve as whatever came before it.

The underground element is the stranger part of the story. A souterrain is a man-made underground structure, typically stone-lined, built during the early medieval period in Ireland as a place of storage, refuge, or both. The one at this site is described as reputed rather than confirmed, which is a useful word. It may correspond to an entry in the Ordnance Survey Letters, the nineteenth-century field notes compiled by scholars working for the Ordnance Survey, which describe a souterrain of several chambers and passages sitting within a circular hut foundation inside a rath. A rath, or ringfort, is the kind of enclosed farmstead that was common across Ireland from roughly the sixth to the twelfth centuries, and the earthwork at Listonavally fits that general shape, even if what remains is fragmentary and partially overwritten by later agricultural boundaries. The description drawing on J. Cuppage's 1986 archaeological survey of the Corca Dhuibhne region gives the enclosure a reference number but stops short of confirming the souterrain's precise location or condition, noting only that the rath itself has been largely destroyed.