The circular enclosure beneath it is a rath, a type of ringfort constructed from an earthen bank and surrounding ditch that served as a farmstead enclosure during the early medieval period, roughly between the fifth and twelfth centuries. Here, that bank still traces a circle some 38 metres across, with remnants of a stone wall surviving along its crest. What makes the arrangement at Ardintenant particularly striking is how completely the later medieval settlement has consumed the earlier one: a tower house sits on the line of the bank to the northwest, and a corner tower occupies the bank to the south, so that the ringfort's perimeter has effectively been pressed into service as a foundation for a later fortified complex.

The rath sits on a gentle east-facing slope, now in pasture, and its original form can still be partially read on the ground. The external fosse, a defensive ditch running from the southwest around to the northwest, survives to a depth of around 1.6 metres in places. A laneway running roughly north to south has cut through the bank to the northeast, and a farm building occupies the southeast quadrant of the interior. A low natural scarp crosses the western half of the enclosure from north to south, an accident of topography that the original builders would have worked around rather than removed. The result is a site where early medieval, later medieval, and agricultural layers have all folded into one another over many centuries, each generation finding the existing landscape useful enough to adapt rather than clear away entirely.