What they would be passing is an early medieval rath, a type of enclosed settlement that once served as a farmstead and homestead for a single family or kin group, typically ringed by one or more earthen banks and ditches as a boundary marker and a measure of modest defence.

This particular example at Largan is subcircular in plan, measuring approximately 30.5 metres north to south and 28.5 metres east to west. A bank runs from the north-west through north to north-north-east, while a low scarp, a slight but deliberate drop in the ground surface, defines the perimeter elsewhere. Internally, at the north-west and south-west, there are traces of what may be stone revetment, that is, facing stones used to stabilise and reinforce an earthen bank from within. The survival of such detail, even in fragmentary form, is relatively unusual and suggests the enclosure was constructed with some care. Within the interior, concentrated in the west-north-west sector, are two small mounds whose purpose is not recorded but which may represent the collapsed remains of internal structures. A gap at the north-east is thought to be an original entrance rather than later damage.

Raths of this kind are found across Ireland in their thousands, most dating to the early medieval period, roughly the fifth to twelfth centuries. What makes this one worth pausing over is the combination of features compressed into a modest space: the earthen bank, the possible stone facing, the internal mounds, and a probable original entrance all surviving together on a ridge that the surrounding scrub has done something to protect from modern disturbance.