Among those overlooked features is a field boundary, recorded as an archaeological monument in its own right, a reminder that this hilltop above Sligo Bay has a layered human history that extends well beyond its most famous occupant.

Field boundaries of this kind, when found in upland or marginal landscapes, are often among the earliest surviving traces of organised land use in Ireland. They can represent anything from Bronze Age land division to medieval or early modern farming enclosures, and the act of classifying them as monuments reflects a broader understanding that ordinary agricultural infrastructure, the walls and banks people built simply to manage animals and mark territory, can be as archaeologically significant as any tomb or ringfort. Knocknarea itself has long been recognised as a landscape of exceptional prehistoric density, with passage tombs, cairns, and enclosures clustered across its summit and slopes, placing even a modest field boundary in considerable company.