What looks at first glance like a natural treeline is in fact the perimeter of a rath, an early medieval earthwork enclosure that once defined a farmstead or dwelling of some local importance. The trees have taken root in the bank itself, which makes the whole thing quietly uncanny to come across in open grassland.

A rath, sometimes called a ringfort, is one of the most common archaeological monument types in Ireland, typically dating to the early medieval period, roughly 500 to 1000 AD, and serving as a defended homestead for a farming family or minor lord. This example at Lisdooaun is nearly circular, measuring 26.5 metres east to west and 25 metres north to south. It is defined by a bank of earth and stone, around 1.6 metres wide, that survives along the northern and north-western arc, while the rest of the enclosure edge takes the form of a scarp, a natural or cut slope in the ground. The bank itself stands only about half a metre on the interior and just under a metre on the outside, modest dimensions that suggest it has weathered considerably over the centuries. Most telling is the entrance: a stone-lined gap, roughly three metres wide, positioned on the eastern side of the enclosure, which was a common orientation for such sites, possibly linked to practical considerations of light and drainage on sloping ground.