A rath, the Irish term for a ringfort, is an enclosed farmstead of the early medieval period, typically dating from somewhere between the fifth and twelfth centuries, built by a farming family for shelter, status, and the corralling of livestock. This one at Farranacardy occupies a low but commanding ridge running east to west, with the ground dropping away sharply to the south and a damp, rush-covered hollow lying immediately to the north before the land climbs again into a ridge that looks back down over the site. The position was clearly chosen with care.

The earthwork measures roughly thirty metres in diameter. Its southern and north-north-western arc is defined by a substantial bank, about four metres wide, rising two metres above the outer ground level, though it has been reduced elsewhere to a lower scarp of perhaps half that height. Around the outside runs a fosse, the term for a defensive or boundary ditch, about four metres wide and still some sixty centimetres deep. The interior platform sits level and enclosed, thickly grown over with irises and nettles, while blackthorn, hawthorn scrub, and several large ash and sycamore trees have taken hold along the bank itself. There is a low gap in the bank at the south-west, around one and a half metres wide, but no corresponding causeway across the fosse outside it, suggesting this is not where the original entrance once stood. A property fence clips the outer edge of the fosse at the north, and a small domed earthen rise within the fosse to the east appears to be the product of more recent disturbance rather than any ancient feature. The rath is overlooked from the ridge to the north, a topographical quirk that would have made the site feel somewhat exposed to anyone approaching from that direction.