The boulder itself is roughly D-shaped in profile, about 2.8 metres along its north-south axis and 1.6 metres wide, with its flat face resting downward. Beneath it, in the sheltered space the arrangement creates, there is a low earthen rise topped with small stones. Scattered around it are a number of loose, larger stones, probably the accumulated debris of field clearance over generations.

What makes this structure genuinely puzzling is that no one can say with confidence what it is. The Megalithic Survey of Ireland examined it and concluded only that it is an artificial megalithic structure, meaning human hands were almost certainly involved in its arrangement, but that there is insufficient evidence to classify it as a megalithic tomb. A megalithic tomb, in the broadest sense, refers to a prehistoric burial monument constructed from large stones, and Ireland has many well-documented variants, including portal tombs, court tombs, and wedge tombs. This structure at Garrycloonagh fits none of those categories cleanly. Its antiquity remains uncertain, and the haphazard appearance of the whole arrangement has not made classification any easier. Whether it was once a more complete monument that has since lost many of its component stones, or whether it was always something less formally constructed, is an open question. Two raths, the circular earthwork enclosures typically associated with early medieval settlement and farming, sit within roughly 100 metres of the structure, one to the northwest and one to the southwest, which places this ambiguous feature in a landscape that was clearly inhabited and worked across a long stretch of time.