Beneath it, a grass-covered earthen bank protrudes roughly two metres northward, visible to anyone who looks closely at where the wall meets the ground. The drystone wall itself stands about 0.9 metres high and is the same across, which is sturdy enough for a field boundary but rather substantial for a simple graveyard enclosure. What lies beneath it is the more interesting question.

The earthen bank is thought to be the remnant of an ecclesiastical enclosure, the kind of curving or circular boundary that early Irish monastic communities used to define sacred ground. These enclosures, often forming a roughly circular or oval perimeter around a church and its associated buildings, were a standard feature of early medieval religious sites in Ireland, and their outlines sometimes survive long after every other trace of the original foundation has disappeared. At An Fál Mór, the bank may date to an early phase of Christian settlement at the site, or it could be roughly contemporary with the Romanesque church that still stands nearby. Romanesque architecture in Ireland generally belongs to the twelfth century, a period of considerable ecclesiastical reform and building activity, so either possibility would place the enclosure within a broadly early to high medieval context. The relationship between the two, buried under a later wall with only a low grassy swell to suggest anything is there at all, remains unresolved.