That a modern thoroughfare bisects what was once a unified sacred precinct is not unusual in Ireland, where roads were laid without much ceremony across older boundaries, but it does make the full extent of this enclosure oddly hard to read at ground level.

The enclosure itself is substantial: roughly 430 metres along its north-west to south-east axis and 250 metres across, sitting on a north-facing slope that is now given over to tillage. Its boundary is an earthen bank standing about 1.5 metres high, with some traces of stone facing still visible in places, and a shallow external fosse, or ditch, running along the outer edge. This kind of layout, a large oval or sub-circular earthwork enclosing a religious site, is typical of early medieval ecclesiastical foundations in Ireland, where the enclosed area served not just as a sacred precinct but as a community space, often incorporating burial grounds, ancillary buildings, and sometimes a small settlement. At the centre of this one sits a graveyard that once held the medieval parish church of Cullen, and more recently a Church of Ireland building that has since been demolished. The layering here is considerable: an early Christian enclosure, a medieval church built within it, and a later Protestant church occupying the same ground before its own disappearance.