It is roughly circular, measuring about 24 metres north to south and 21.5 metres east to west, with an internal bank height of up to 1.3 metres. Heavily overgrown now, it is the kind of feature that a casual walker might dismiss as a natural undulation, yet its proportions are too consistent, too considered, to be anything of the sort.

This is a rath, the most common monument type in the Irish landscape. Raths, also called ringforts, are enclosed farmsteads built predominantly during the early medieval period, roughly between the fifth and twelfth centuries. Their earthen banks, sometimes topped originally by a timber palisade, defined a family's living space and offered a degree of protection for livestock. Thousands survive across Ireland, many on private farmland, quietly embedded in field systems that have grown up around them over the centuries. The Lissaclarig example is modest in scale, comparable to a typical single-family enclosure rather than the larger, more elaborate sites associated with higher-status occupants. The heavy vegetation that now obscures its bank is itself a kind of record, suggesting the site has been left largely undisturbed, which is not always the case for monuments of this type in agricultural areas.