That designation alone is worth pausing over. Field boundaries are among the most unassuming features in the Irish landscape, easy to dismiss as purely agricultural and therefore modern, yet many such boundaries preserve the outlines of land divisions that are centuries or even millennia old. A low earthen bank or a dry-stone wall running between two fields can, on closer inspection, reflect patterns of land use stretching back to the early medieval period or beyond.

Mayo's landscape is dense with this kind of layered history. The county contains some of the best-preserved ancient field systems in Europe, most famously the Neolithic landscape buried beneath the Céide Fields bog in north Mayo, where stone-walled enclosures dating to around 3500 BC still lie largely intact beneath the peat. Not every recorded boundary carries such antiquity, but the act of formally designating a field boundary at Ballyheer suggests it possesses characteristics, whether in its alignment, construction, age, or relationship to surrounding features, that set it apart from an ordinary agricultural wall. Unfortunately, the detail that would clarify exactly what those characteristics are has not yet been made publicly available, leaving Ballyheer's boundary in a curious limbo: acknowledged, protected in principle, but not yet explained.