Measuring roughly 80 metres northwest to southeast and 78 metres east to west, it is a substantial feature by any measure, yet its defining elements, two banks and an intervening fosse, have been worn down to the point where much of the circuit survives only as a low, irregular scarp. A fosse is simply a ditch, typically dug to accompany and reinforce an earthen bank, and in this case the fosse remains the most legible part of the monument, its outline still clearly traceable on aerial photographs even where nothing much is visible on the ground.

What makes the site particularly layered is the presence of a rath overlying its northeastern quadrant. A rath is a ringfort, the kind of enclosed farmstead built across Ireland during the early medieval period, roughly between the fifth and twelfth centuries, and their construction on top of earlier enclosures was not uncommon. The earlier enclosure at Clogharoasty is likely prehistoric, though its precise date and function remain uncertain. Adding a further complication, the modern townland boundary cuts directly through the monument at two points, north and south-southeast, a reminder of how administrative lines drawn across the landscape centuries after a site was abandoned can fracture the archaeology beneath them, dividing a single monument between jurisdictions as though it were ordinary ground.