The boundary at Ballyheer, in County Mayo, is one such feature, a line drawn across the landscape that has been deemed worth preserving in the national record, even if the precise reasons remain, for now, unavailable to the general public.

Field boundaries in Ireland can range from Bronze Age land divisions to post-medieval enclosures thrown up during the reorganisation of farming under improving landlords. In the west of Ireland particularly, some boundaries fossilise patterns of agriculture that predate the catastrophe of the nineteenth century, preserving in stone and earthwork the outlines of a landscape that was radically altered by famine, emigration, and clearance. Without the specific research detail for Ballyheer being publicly accessible at present, it is not possible to say which period this boundary belongs to, or what feature of its construction or setting prompted its formal recognition. That ambiguity is itself a small reminder of how much of the Irish landscape has been catalogued but not yet fully interpreted.