It skirts the western half of the enclosure, quietly eroding the bank that has defined this circular patch of Kerry farmland for well over a thousand years, and the slight downward slope of the western interior suggests the water has already made its point. It is an oddly intimate kind of decay, the sort that reminds you these structures were never inert monuments but features of a working landscape that never stopped changing around them.

A rath, as ringforts of this earth-and-stone construction are commonly called, was typically the enclosed farmstead of an early medieval family, most dating to somewhere between the sixth and tenth centuries. The one at Coolies sits in level pasture roughly forty metres south-west of a ford on the Owgarriff River, a placement that speaks to the practical logic of its builders: fresh water and a river crossing close at hand, the enclosure itself slightly raised above the surrounding ground. The bank, which measures about eight and a half metres wide and retains stone facing on both its inner and outer faces, forms a near-complete circle roughly thirty-seven metres across. A formal entrance, four and a half metres wide, opens at the south. Along the eastern arc, weathered rocks still sit on top of the bank. In the north-west quadrant, just inside that bank, there is a shallow depression, roughly sixteen metres by five and half a metre deep, the purpose of which is not recorded but which is the kind of detail that tends to nag at the curious.