The site is sub-rectangular in shape, roughly fifty metres north to south and ninety metres east to west, and it tilts down a steep north-facing slope, so the ground beneath the headstones is noticeably uneven underfoot. The enclosure boundary shifts in character as you move around it: a stone wall to the south, and a stone-faced earthen bank elsewhere, the kind of boundary that suggests long, incremental construction rather than a single planned effort.

The enclosure itself predates anything visible above ground by a considerable margin. Early ecclesiastical enclosures in Ireland are typically oval or sub-rectangular boundaries that mark the original footprint of an early medieval religious settlement, often dating back to the early Christian period. Within this one at Knockmacool, the southern half still holds a Church of Ireland church alongside the recorded site of an older church, the two layered together in a way that reflects centuries of religious use on the same ground. The headstones in the graveyard run from the mid-eighteenth century to the present day, with family vaults among the more modest grave markers, the older stones and the newer ones sharing the same tilting slope without obvious hierarchy.