The site is known as Lisnacarheen, or Lios na Ceártan in Irish, and what survives there is a layered puzzle: a ringfort whose interior holds not only the expected traces of early medieval habitation but also a drystone rectangular building that appears to be a later addition, and beneath the ground, a damaged but still partially intact souterrain, the kind of underground stone-lined passage used in early medieval Ireland for storage, refuge, or both.

A univallate rath, meaning a ringfort enclosed by a single bank and ditch, Lisnacarheen has an internal diameter of about 22 metres. Its enclosing bank is roughly 5 metres wide and a metre high, though the south-eastern section has been removed entirely. Inside, low banks of earth and stone extend inward from the perimeter, and drystone facing along the north-eastern inner edge may indicate the positions of former hut-sites. The rectangular building, measuring at least 7 metres by 3.5 metres internally with walls up to 1.2 metres high, has been locally identified as a forge, which would place its use well outside the ringfort's original early medieval context. The souterrain running beneath the site is an L-shaped passage, its walls built of upright stone slabs topped with drystone walling and roofed by eight flat slabs. A separate air-vent opens near the north-eastern corner, and traces of a third passage, aligned at right angles to the existing L-shape, were uncovered during excavation, though its full extent is unknown. An Ordnance Survey notebook recorded that the souterrain once terminated in a small building with a fireplace, though no trace of that feature remains. J. Cuppage documented the site in the 1986 Corca Dhuibhne archaeological survey of the Dingle Peninsula, by which point the souterrain had already suffered considerable damage.