It looks, at first glance, like a particularly purposeful field boundary, which in a sense it is. But its scale and straightness suggest something older and more deliberate than an ordinary agricultural division.

The historian William Carrigan, writing in 1905 in his multi-volume history of the diocese of Ossory, described what he found on Graine Hill as a fence "resembling a rampart, very strong and very old." His instinct was that this earthwork was no mere property marker but something that predated the administrative landscape as it came to be formalised. He proposed that it likely served as a forerunner of the county boundary itself, a pre-modern territorial line that later cartographers and administrators may have followed when drawing the limits of Co. Kilkenny. Linear earthworks of this kind are not uncommon in Ireland; they were used across different periods to define land, assert authority, or mark the edges of political territories, and they often outlasted the kingdoms or communities that built them by many centuries. The fact that this one sits so precisely along a hilltop, running with that kind of deliberate straightness Carrigan noted, is what sets it apart from the workaday ditches and banks of later farming practice.