Known as Lisduff or An Lios Dubh, this early medieval enclosure on the east bank of the Garfinny river in County Kerry was originally a complete circle, but repeated flooding has claimed the entire western half of the earthwork, leaving that side of the site defined not by a bank and fosse but by a sheer drop of 2.2 metres down to the river's narrow flood plain. What remains is effectively a half-moon of surviving archaeology, still coherent enough to read clearly but altered beyond recovery on one side.

The surviving portion belongs to the type known as a univallate rath, meaning it was defended by a single earthen bank and accompanying fosse, or ditch, rather than the double or triple circuits found at more elaborate sites. Here the fosse runs roughly four metres wide at its base and about one and a half metres deep, and the bank beyond it rises nearly four metres on its outer face, considerably more imposing from outside than the 1.4 metres of height it presents to someone standing within. The south-facing entrance is a modest gap of around 1.5 metres through the bank, with a causeway bridging the fosse below it; two large boulders are set into the outer face of the bank to flank the opening, and a third lies fallen across the gap itself. Inside, the southeast sector preserves something stranger still. An oval structure visible on older Ordnance Survey mapping has since collapsed to a spread of rubble roughly 5.8 by 4 metres, abutting the inner face of the bank, which at that point carries a stepped stone facing. Immediately to the north of this collapse, a hollow faced on two sides with drystone walling may be the entrance to a souterrain, an underground passage or chamber of the kind commonly built within raths during the early medieval period, typically used for storage or concealment. The 1986 Dingle Peninsula archaeological survey by J. Cuppage first documented the site in detail and remains the primary record of its form.