A souterrain is an underground stone-lined passage or chamber, typically associated with early medieval settlement, used variously for storage, refuge, or both. Its presence here suggests this raised circular enclosure was once a working farmstead of some consequence, not merely a defensive ring thrown up in haste.

The rath itself sits on a rise in pasture at Shanvally, with views across undulating terrain and a broad stretch of wet land to the north-east. It is roughly circular, measuring 34.2 metres north to south and 34.4 metres east to west, and defined by the intermittent remnants of an earthen bank. That bank survives best at the north, north-east, south-east, and south-west, where it still stands up to 1.8 metres on its outer face, though it has been reduced to a scarp elsewhere. Centuries of practical use have left their mark: the bank has been modified along part of its circuit to serve as a field boundary, faced with stone in sections, and a ten-metre stretch at the west-north-west has been quarried away entirely. Outside the bank to the north-north-east, a slight depression thick with nettles may be the ghost of a fosse, the ditch that would originally have reinforced the enclosure's defences. There are two more substantial gaps in the bank, one 2.5 metres wide at the north-north-east and a slumped opening 1.4 metres wide at the east, the latter a plausible candidate for the original entrance. Several narrower breaks have been opened up more recently by cattle.

The interior today is level and grassy, kept that way by the same grazing animals that have gradually worn at the bank's edges. The tree ring gives the whole enclosure a quietly self-contained quality, set apart from the surrounding farmland even though the land has long since absorbed it into its working rhythms.