The circular enclosure is modest, around twenty metres across, and what remains of its earthen bank has been worn down to little more than a low, intermittent ridge, barely a tenth of a metre high in places. Mature holly and oak have taken root across the uneven interior, and gorse has crept up the flanks of the hillock, softening the outline of what was once a deliberately shaped, inhabited place.

This is a rath, the Irish term for a ringfort, a type of enclosed farmstead built predominantly during the early medieval period, roughly between the fifth and twelfth centuries. Thousands survive across Ireland in varying states of preservation, and they represent the most common field monument in the country, yet each one conceals its own particular detail. At Curragh, that detail is a souterrain, an underground stone-lined passage or chamber, situated near the centre of the interior. Souterrains were typically used for storage or as places of refuge, and their presence within a rath is relatively common, though it always adds a subterranean dimension to what can otherwise look like a simple earthwork. The site has been disturbed across its entire extent, hillock and all, which makes the survival of any readable trace of the bank, and of the souterrain beneath, all the more notable. Roughly 130 metres to the north-east, another rath and its own associated souterrain survive, suggesting this stretch of ground was once home to more than one early medieval household, settled in close proximity along the same riverbank.