The site sits on a south-west-facing slope of a low hillock in undulating County Tipperary countryside, and whoever built it did not simply follow the contours of the ground. Instead, the interior was raised and shaped to create a flat platform, a detail that is easy to overlook but speaks to a deliberate investment of labour. The result is a large circular enclosure, roughly 56 metres across at its widest, enclosed by an earth and stone bank and, on its north-east through south-east arc, a surviving outer fosse, the term for a defensive ditch, that runs between three and seven metres wide and up to two metres deep. Elsewhere the fosse has been filled in over the centuries, leaving only the bank visible.

Ringforts, also known as raths, are among the most common early medieval monument types in Ireland, typically serving as enclosed farmsteads for a family of some standing between roughly the fifth and twelfth centuries. This one at Lisnamrock is in notably good condition: the bank survives to an external height of 2.7 metres along its best-preserved northern and eastern arc, and the interior remains intact. A probable original entrance gap sits at the south-east, around two metres wide, while smaller gaps on the south-west and north-north-east are almost certainly later livestock gaps, the kind of practical alteration farmers have been making to earthwork boundaries for generations. A stream runs about 60 metres to the south-west, a detail consistent with the practical water requirements of an early medieval farmstead. The ruins of an abandoned farmhouse lie 50 metres to the north, and older Ordnance Survey mapping records field boundaries that once attached to the ringfort at its north and south, since removed. Notably, the site does not stand in isolation: another ringfort lies approximately 300 metres to the east, a possible ringfort around 240 metres to the south, and a further enclosure 250 metres to the south-west, suggesting this part of Tipperary was once a settled and managed agricultural landscape.