Near the top of an east-facing slope on a north-south drumlin ridge, one of the countless elongated hills shaped by retreating glaciers across the Irish midlands, a circular earthen platform survives in grass and rush. It measures roughly 30.5 metres east to west and 29 metres north to south, dimensions consistent with a rath, the Irish term for a ringfort, which was typically a defended farmstead enclosed by one or more earthen banks and ditches. Thousands of these survive across Ireland, but each one marks a particular family's decision, at some point between roughly the fifth and twelfth centuries, to enclose their household on a chosen piece of ground.

At Prughlish, the enclosing features are worn but still readable. A scarp, essentially a steep drop in the ground surface forming one edge of the old boundary, rises from about 0.3 metres at the north to 0.8 metres at the east, where the slope would have offered a natural advantage. A slight trace of a bank survives at the south-west, around 4.5 metres wide and 0.2 metres high internally, a ghostly remnant of what was once a more substantial earthwork. Beyond it, a fosse, the external ditch that accompanied the bank, runs between roughly 2.4 and 4.6 metres wide, and its presence today is betrayed less by obvious earthwork than by a band of rushes, those plants that reliably colonise waterlogged or disturbed ground. No original entrance has been identified, which is not unusual where the earthworks have been softened by centuries of agricultural use and weathering.