Half-buried in the grass is a raised semicircular platform, its straight edge running roughly north-north-east to south-south-west for about 26 metres, with the curved section pushing some 14 metres out to the west-north-west. The whole thing is defined by a scarp, a steep earthen face rising to around 1.6 metres, with a slight internal lip along the top edge. On its south-east side it has quietly merged with a modern field boundary, the ancient and the agricultural sitting side by side without ceremony.

Locally, people call it "the lios", the Irish word for a ringfort enclosure, and the name carries more information than it might first seem to. Ringforts, known variously as raths or lioses depending on regional usage, were the enclosed homesteads of early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries. They are the single most common archaeological monument type in the Irish countryside, yet this one at Horsemount is unusual in being only semicircular rather than the more typical full ring. Whether the straight side represents a deliberate design choice, a later truncation, or the result of the slope and the field boundary claiming part of the original circuit over the centuries is not recorded. What survives is modest in scale but coherent enough to read clearly on the ground, a raised interior platform with its defining earthwork still standing to a meaningful height after well over a thousand years of ploughing seasons and grazing animals around it.