The earthwork is easy to miss: the enclosing bank survives to only about 0.4 metres above the interior, and the surrounding terrace, roughly ten metres wide and dropping away in a low scarp, could read at a glance as nothing more than natural ground movement. But the proportions are deliberate, the oval measuring approximately 20 metres across on its longer axis, and the relationship between the raised interior and the sloping terrace outside it follows the pattern of a rath, the Irish term for a ringfort enclosed by earthen or stone banks.

Ringforts of this kind were the most common settlement form in early medieval Ireland, broadly from the fifth to the twelfth centuries. They functioned as farmsteads, the enclosing bank and any associated ditch providing a degree of security for people and livestock rather than a serious military fortification. Most were home to a single family and their animals. The Larkhill example sits on its hillock in the way such sites often do, using modest elevation to improve visibility across the surrounding land. The stony bank, now largely collapsed to a low remnant 3.5 metres wide, suggests the structure was built at least partly from stone rather than pure earthen construction. A pile of stones covered in brambles rests against the bank on the eastern side, possibly the remains of a building or a later clearance. A field boundary wall, running roughly north-northeast to south-southwest, has been built directly over the outer terrace along the western and northwestern arcs, the kind of quiet overwriting that happened to countless such sites as agricultural patterns shifted across the centuries. Gorse has taken hold along the south-western slope, obscuring the outer edge further in that direction.