It measures approximately 27 metres across its east-west axis, which puts it within the typical size range for a rath, the Irish term for a ringfort enclosed by an earthen bank rather than stone. These features, built predominantly during the early medieval period, roughly the fifth to twelfth centuries, served as enclosed farmsteads for a single family or small community. Thousands survive across Ireland, yet individually they are easy to overlook, folded into working farmland and quietly reclaimed by vegetation.

The earthen bank that defines this example is the main visible feature, though both it and the interior are currently inaccessible because of the density of the vegetation that has grown up around and within the site. That overgrowth, frustrating as it is for close inspection, is also a kind of passive protection; undisturbed ringforts often preserve beneath their banks evidence of original construction, and sometimes souterrains, which are stone-lined underground passages associated with storage or refuge, remain intact below ground. Without excavation, what lies inside the Lissanoohig enclosure remains unknown.