Lisnadurraha is a rath, the kind of circular earthwork, typically dating from the early medieval period, that once served as a farmstead enclosure, defined by an earthen bank, a fosse or ditch, and sometimes an outer bank beyond that. What makes this particular example quietly interesting is the way it has been absorbed, and in places dismantled, by the working landscape around it. Later field boundaries cut across its fosse, a post-and-wire fence runs along the top of its outer bank to the south, and on the northern arc the outer bank has been removed entirely. The rath has been farmed around and over for centuries, and the scars show.

The name Lisnadurraha appears on Ordnance Survey maps from as far back as 1838, which at minimum confirms the site was known and named before any modern surveying interest in it. The earthwork itself is roughly circular, measuring forty metres across, with an inner bank that still stands to nearly two metres on the southern side. A fosse three metres wide survives on the southern half, with its own external bank alongside it, though on the north-eastern arc the ditch has vanished altogether. The original entrance was on the eastern side, where a gap of just over two metres remains in the inner bank, and there are faint traces of a causeway that would once have bridged the fosse. A corresponding gap in the outer bank exists, though it is now blocked by a field fence. Inside the enclosure, slightly east of centre, there is a low, poorly defined mound about ten metres across whose purpose is unclear. More puzzling still is a single upright slab in the north-west quadrant, half a metre high and protruding from the grass without obvious explanation. Gorse has colonised the perimeter, and a small quarry pit sits just outside the outer bank to the south-east, a reminder that the site has been a practical resource as much as an ancient monument.