At Grange in County Dublin, though, that curve in the southern boundary is not a builder's quirk or a later adjustment to accommodate a road. It is, most likely, the surviving trace of an early ecclesiastical enclosure, the kind of roughly circular boundary that defined monastic and church settlements in early medieval Ireland, demarcating sacred space from the secular world beyond.

The full picture only became clear in 2003, when a geophysical survey carried out by Nicholls revealed not one but two concentric enclosures beneath and around the existing church and graveyard. The inner enclosure measures approximately 100 metres in diameter, the outer around 200 metres, and together they form the characteristic double-ring layout associated with early Irish ecclesiastical sites, where an inner precinct might house the church and clergy quarters, and an outer zone accommodated ancillary functions such as crafts, agriculture, or the dwellings of lay dependants. The survey also identified field boundaries and smaller ancillary enclosures within the complex. As Mac Shamhráin noted in 2004, the road that now runs through the site bisects the enclosure system entirely, meaning that what was once a unified sacred landscape has long since been divided by later infrastructure without anyone necessarily realising what lay underneath.

The site sits alongside the extant church and graveyard at Grange, and much of what the geophysical survey recorded remains below ground, invisible to the casual eye. The curved wall section at the southern end of the graveyard is the most legible surface feature, and it rewards a slow walk around the perimeter. Because the enclosures are not excavated and have no visitor infrastructure, the experience is one of reading the landscape rather than inspecting exposed archaeology. Knowing that a road cuts straight through what was once the outer boundary gives the whole area a slightly different character, as though the ordinary and the ancient are occupying the same ground without either quite acknowledging the other.