That slight rise in the earth is not a landscaping choice or an accident of drainage. It is most likely the surviving remnant of an early medieval ecclesiastical enclosure, the kind of oval or circular boundary that once defined sacred space around an early Irish church site, long before the present building took shape.

The evidence for this reading comes from several layers. The Ordnance Survey six-inch map of 1936 records a roughly oval enclosure around the church, measuring approximately 55 metres in length and 46 metres in width, and this outline still traces through the landscape today. The graveyard wall along the eastern side, dated to 1712, appears to follow the same curving line, continuing it around to the south-west. So the eighteenth-century builders of that wall were, knowingly or not, reusing an alignment that may be many centuries older. The raised platform in the north of the graveyard is the most physically legible section of that earlier boundary, though it has been interrupted by the later insertion of the Domville family tomb, cutting across what would otherwise be a continuous earthen arc.

Santry is now well within the suburban spread of north Dublin, and the graveyard sits beside a church in an area that sees considerable everyday traffic. The 18th and 19th century memorials scattered through the site are worth reading carefully, but the more unusual feature demands attention in the northern section, where the ground visibly lifts and the sycamores mark the curve. Looking from there back towards the church, the oval shape of the whole enclosure becomes easier to imagine. The Domville tomb, for all that it disrupts the earlier feature, is itself a piece of local history worth noting as a marker of one of the area's prominent landowning families.