Beneath and between the present-day field boundaries, an older field system survives, its outlines legible in the landscape as the accumulated work of generations of farmers who divided, cultivated, and managed this ground long before the current pattern of ownership took shape. Field systems of this kind are among the more easily overlooked categories of archaeological monument, partly because they blend so readily into working farmland, and partly because their significance is cumulative rather than dramatic. A surviving field system is not a single event but a layered document, capable of preserving evidence about land use, settlement, and agricultural practice across centuries.

Ireland retains a remarkable number of ancient field systems, some dating to the Bronze Age or earlier, preserved where later cultivation did not disturb them. The west of Ireland in particular, where blanket bog has in places sealed pre-historic boundaries beneath peat, has yielded some of the most significant examples known anywhere in Europe. Whether the Kilcooly system belongs to that deep prehistoric past or to a more recent period of agricultural organisation, such as the medieval or post-medieval era, is a question the available record does not currently answer in detail. What can be said is that its recognition and recording as a monument reflects a broader understanding that the arrangement of fields is itself a form of evidence, as worthy of attention as a ringfort or a souterrain.