Its boundary is sub-circular rather than the rectangular or irregular outline you might expect of a later churchyard, and that curve in the land is significant. Circular or near-circular enclosures are a hallmark of early Irish ecclesiastical sites, where a founding community would mark sacred ground with a curving ditch or bank, often long before any stone church was raised within it. The outline at Crumlin hints that something of that early monastic or ecclesiastical tradition persisted here, quietly legible in the shape of the walls long after the original reasons for it were forgotten.

Archaeological work carried out in 1998 confirmed that the circular form was not accidental. An assessment that year, reported by Hayden in 2000, revealed a ditch running outside and concentric to the existing churchyard boundary, suggesting the graveyard wall itself traces the line of an earlier inner enclosure. No datable finds came out of that ditch, so a precise period cannot be firmly attached to it, though two pits containing burnt material found inside the ditch are considered likely to be medieval in date. A second phase of investigation in 1999 added another layer to the picture: a further ditch feature was found crossing the site from east to west, which may represent an outer enclosing element, a second ring wrapping around the first. That outer ditch appears to have been deliberately filled in during the later medieval period, according to Murphy's 2000 report, suggesting the site was actively managed and reorganised over several centuries rather than simply abandoned.

Crumlin village sits within the modern city, and the graveyard is not remote or difficult to reach, though it is easy to pass without registering its age. The sub-circular form is best appreciated on a map or aerial view rather than from street level, where the curving wall blends into the surrounding urban fabric. There is no visitor infrastructure as such; this is a working graveyard in a residential area. The archaeological interest lies beneath the surface, in features no longer visible, so what a visitor is really reading here is the shape of the boundary itself, and what that gentle curve implies about the generations who first chose and marked this ground.