Lislahardane, from the Irish Lios an Leath Ardáin, translates roughly as the ringfort of the half-little height, a quietly precise description of a place that was clearly chosen for the modest elevation it commanded over the North Kerry countryside. Ringforts, or raths, are among the most common field monuments in Ireland, typically circular enclosures built during the early medieval period as enclosed farmsteads for a family and their livestock. What makes this one worth attention is its scale and the quality of its preservation, both of which exceed what you might expect from a monument whose name gestures at something small and half-formed.

The enclosure has an internal diameter of 49 metres, surrounded by a single earthen bank that rises to a maximum external height of 5 metres and an internal height of 4 metres. In places, and most visibly to the south-south-east, the bank appears to be stone-lined rather than purely earthen. Beyond the bank runs a U-shaped fosse, which is simply a defensive ditch, cutting around the monument from the north-north-east through to the north-west and south-west. It measures 3 metres wide and 1.8 metres deep. The interior sits at a higher level than the surrounding ground, which contributes to the site's overall sense of deliberate elevation. Within the interior, three distinct mounds of stone are visible in the north-east, east, and southern sectors, measuring roughly 10 by 4 metres, 4.2 by 2 metres, and 5 by 3 metres respectively. Their purpose is not specified in the available record, but such stone accumulations within ringfort interiors are sometimes the remains of collapsed structures or later clearance activity. The entrance, around 6 metres wide and oriented to the south-south-west, may originally have been stone-lined as well, giving the whole enclosure a more substantial character than the earthen exterior alone suggests.