It is not dramatic in scale, measuring roughly 27.5 metres north to south and 24 metres east to west, but the detail in its construction is quietly telling. The northern and north-eastern arc is defined by a proper earth and stone bank, about three metres wide, faced on its outer side with large stones and kerbed internally; the rest of the perimeter drops away as a steep scarp about 1.2 metres high. A ring of hawthorn has colonised the outer edge, and the interior is largely grass-covered, with some scrubby overgrowth filling the gaps.

This is a rath, the Irish term for a ringfort, the most common type of early medieval settlement monument in Ireland. Ringforts were typically enclosed farmsteads, built between roughly the fifth and twelfth centuries, where a family and their livestock could be protected within a bank and ditch or, as here, a raised scarped enclosure. The quality of the stonework at Ballysumaghan, with its external facing and internal kerbing, suggests this was a reasonably substantial example of the type. The 1838 Ordnance Survey six-inch map recorded trees within the interior, long since gone, which is a small reminder of how much the surface character of these sites shifts over time even while the underlying earthwork persists. Notably, a second circular enclosure sits approximately 100 metres to the south-south-east, which raises the possibility that these two features were once part of a related cluster of activity in this corner of the townland of Ballysumaghan.