The surrounding field fences have been removed, which means the earthwork is now more legible than it might otherwise be, its roughly circular outline measuring around twenty-five metres east to west and twenty-three metres north to south. What marks it out is how much of its original structure persists: the enclosing earthen bank still rises to about 1.2 metres on the interior, and the external fosse, a defensive ditch running from south-south-east to east-north-east, survives to a depth of roughly a metre, with the southern portion remaining waterlogged. A clearly defined entrance gap, about 2.6 metres wide, opens to the south-east.

This is a rath, the Irish term for a ringfort, the most common type of early medieval settlement monument found across Ireland. Raths were typically built between roughly the sixth and tenth centuries and served as enclosed farmsteads, the earthen bank and ditch providing both a degree of physical security and a visible marker of status for the farming family within. Thousands survive across the country in various states of preservation, though many have been levelled by centuries of agriculture. The Derryleigh example is modest in scale, as most raths are, but the persistence of its fosse and the legibility of its entrance give a reasonably clear picture of what these enclosures originally looked like. The waterlogging in the southern section of the ditch is a reminder that the site was partly shaped by the local hydrology, the nearby stream likely influencing how water moved through and around the earthwork.