Sitting in level pasture in Lissaniska West, County Limerick, this ringfort is a roughly circular enclosure measuring forty-two metres north to south and just over forty metres east to west, and the engineering logic behind it becomes clearer the longer you stand beside it.

A ringfort, or rath, is an enclosed settlement type that was widespread in early medieval Ireland, typically dating from around the fifth to the twelfth century, and usually built to protect a family farmstead and its livestock. This particular example is enclosed in two different ways depending on where you stand around its circumference. From the east-northeast around to the east-southeast, the boundary takes the form of a conventional earthen bank, which rises only about thirty centimetres on the interior side but reaches over two metres in height on the outside. For the remaining arc, from the east-southeast back around to the east-northeast, the enclosure is defined instead by a scarped edge, essentially a deliberately cut and shaped slope, standing roughly 1.9 metres high and two metres wide. Running around the full circumference is an external fosse, a ditch, dug to a depth of 1.3 metres and about 2.3 metres across. A modern field boundary has been laid along the outer edge of the fosse between the southwest and south-southeast, tidily following the ancient line. The record was compiled by Denis Power and uploaded in August 2011.

The interior is level, dry, and clear of overgrowth, which makes it unusually legible for a monument of this kind. The variation in construction method around the perimeter is worth paying attention to once you are on site, since the shift from built-up bank to scarped edge is not always obvious from a distance but becomes clear as you walk the outer edge. The fosse, too, retains its definition well. The site sits on private farmland, so access would require the landowner's permission, but the flat, open character of the surrounding pasture means the earthworks read clearly from the field margins.