It is not. The monument is a henge, a type of prehistoric ceremonial enclosure defined by a bank and an internal ditch rather than the other way around, which is precisely what makes henges so peculiar. Most defensive earthworks place the ditch on the outside to keep things out; a henge inverts this logic, with the bank thrown up on the outer edge and the fosse, or ditch, dug on the inside. Whatever was happening within these monuments, it was not a military matter.

The Garryard henge is roughly circular, measuring approximately 77.7 metres in one direction and 74.9 metres in the other, making it a substantial monument by any measure. The interior, a flattened area of around 40 metres across, sits slightly higher than the surrounding farmland, giving it a faint raised quality. The bank survives well across most of the site, ranging from 6.6 to nearly 11 metres in width, and is broadly flat-topped except where a secondary outer ditch, probably not part of the original construction, runs along the northeast and southwest sectors. There, the bank takes on a more terraced profile, and archaeologist Paddy O'Donovan, writing in the North Munster Antiquarian Journal in 1985, argued that later field-builders most likely heightened the bank by digging out material from that outer ditch, quietly cannibalising one ancient feature to reinforce another. The entrance survives clearly: a gap of nearly ten metres in the bank and fosse facing roughly east-southeast, wide enough to feel deliberate and formal. Unfortunately, a modern road and associated drainage works have cut through and levelled the northwestern arc of the monument, and that lost section survives today only as faint variations in the vegetation, a ghost of earthwork just barely legible in the grass.