The rath at Lacka is not a dramatic ruin. It is, by any measure, a modest and poorly preserved one, and that modesty is precisely what makes it interesting: it survives not as a monument but as a faint insistence, a low ring of earth still holding its shape against the landscape above Kenmare Bay.

A rath is an early medieval ringfort, typically a circular enclosure defined by one or more earthen banks, used as a farmstead and place of habitation. This one is univallate, meaning it has a single enclosing bank rather than the two or three rings found at more elaborate examples. That bank measures roughly 32 metres across north to south and 31 metres east to west, with a flat crest about 2 metres wide and a height of around 1 metre on both its inner and outer faces. There is no clear surviving entrance. What makes the site particularly intriguing is the reported presence of a souterrain, a stone-built underground passage or chamber of the kind often associated with early Irish settlement, sometimes used for storage or refuge. The opening was said to be in the eastern bank, where a cluster of large boulders is incorporated into the earthwork, but by the time surveyors reached it, the entrance had been closed up. Local knowledge placed it there; the ground itself gave nothing away.

The site overlooks Kenmare Bay to the south, which offers some sense of why this particular slope was chosen for habitation, though the view is largely obscured now by the vegetation that also frustrated any detailed examination of the archaeology. The boulders in the eastern bank remain visible, and they mark roughly where the sealed souterrain is reputed to lie, a detail easy to miss without knowing to look for it.