This is a rath, the Irish term for a ringfort, the kind of enclosed farmstead that once numbered in the tens of thousands across Ireland, typically dating from the early medieval period. What makes this particular example worth a second look is a curious detail in its western interior: a zig-zag shaped hollow pressed up against the inner edge of the enclosing bank, which may be the remains of a collapsed souterrain.

A souterrain is an underground passage or chamber, usually stone-lined, built beneath or adjacent to a ringfort. They served various purposes, among them storage, refuge, and ventilation for dwellings above. When the roof of such a passage collapses over time, it leaves behind exactly the kind of irregular, angular depression visible here. The rath itself is oval in plan, measuring roughly 23 metres east to west and 17 metres north to south internally, enclosed by a bank about three metres wide and standing to around 0.70 metres in height. A formal entrance gap, just under two metres wide, opens on the eastern side, with a corresponding ramp easing the transition from outside ground level into the raised interior.