It sits directly on top of a much older fosse, the outer ditch of an early ecclesiastical enclosure, and the internal bank of that original boundary was incorporated into the wall itself. In effect, the modern stonework is a kind of skin stretched over the skeleton of a far earlier sacred boundary, one that predates the gravestones within by many centuries.

The graveyard at Rathcusack is roughly circular, about 63 metres across in total, with a medieval church placed at its centre. Circular ecclesiastical enclosures of this kind are a recognised feature of early Irish Christianity, their shape often thought to reflect pre-Christian practice or simply the practicalities of marking out a sacred precinct. The headstones clustered in the western half of the enclosure are relatively recent by the standards of the site; the historian William Carrigan, writing in 1905, recorded the earliest stone he could find as dating to 1723. Nothing earlier survives in legible form above ground, though the layers beneath the wall tell a longer story. The site sits on a gentle west-facing slope, with the River Nore running about 300 metres to the west, and open views across the countryside to the south, west, and north.

The graveyard is accessed from the east through a gate flanked by capped stone piers, with a public road running close along the same side. Walking in and then turning to look westward, the concentration of headstones draws the eye, but it is worth pausing at the boundary wall itself, where the ground rises slightly on the inner face, the remnant of that early bank still holding its shape after more than a thousand years.