Look closer and the trench gives something away: it is narrow and unusually steep-sided, and the evidence suggests it replaced an earlier, shallower fosse, the term for the defensive ditch that traditionally enclosed a rath, or ringfort. That earlier depression is still faintly legible beneath the later cut, a palimpsest of different moments of reshaping laid one over the other in the soil.

A rath is a roughly circular earthen enclosure, typically built during the early medieval period in Ireland, between roughly the fifth and twelfth centuries, and used as a farmstead or settlement protected by its raised bank and surrounding ditch. This particular example in Balrath measures around thirty metres in diameter, with a bank standing just under a metre high. It was recorded on the Ordnance Survey twenty-five-inch map of 1913 as a roughly oval earthwork, and a more detailed description from 1970 noted that the interior rises noticeably towards a level area at the centre, a feature consistent with deliberate construction rather than natural topography. At the south-south-east, a causeway, nearly eight metres wide overall and just over four metres across its top, interrupts the line of the bank and fosse. This is likely the original entrance, the point where people and animals would have passed in and out of the enclosed space. The fosse at this point swings away from the base of the bank's inner slope, a detail that reinforces the sense that the ditch has been altered at some stage, perhaps deepened or recut by later hands with purposes quite different from the original builders.

The monument is now covered in trees, which makes it visible on aerial photography as a distinct oval of woodland set against open farmland. The elevated position would once have offered clear sightlines across the surrounding landscape in all directions, a practical advantage for whoever lived within its banks.