Twenty metres of it are now visible: a line of boulders and intermittent upright stones running east to west, close to the northeastern shore of the lake. It is, in essence, an old field boundary, the kind of structure that once organised farmland across Ireland. What makes it quietly arresting is where it now sits, sealed under the bog, suggesting that the landscape here was once very different.

Cloon Lough occupies a broad valley on the Iveragh Peninsula in south Kerry, flanked by Knocknacusha mountain to the west and Mullaghanattin to the east. The wall lies on low-lying ground less than 200 metres from the lakeshore. The fact that it is buried beneath 45 centimetres of peat indicates that the land was once open enough to farm or graze, before the bog gradually advanced and covered it over. This kind of submerged field system is not unique to Kerry, but each example offers a small, specific reminder that the bogs blanketing much of upland and lowland Ireland accumulated over centuries, slowly reclaiming ground that people had once worked and divided and held.