On a west-facing slope in the quietly rolling terrain of County Tipperary, the ground under tillage gives no hint that anything lies beneath it. Yet aerial photography taken in July 2005 revealed something the surface refuses to show: a roughly circular cropmark approximately 35 metres in diameter, the kind of ghostly imprint that suggests an enclosure of some kind once stood or was cut into this hillside.

Cropmarks appear when buried features, whether ditches, walls, or banks, affect how plants above them grow. Soil disturbed by an ancient ditch tends to retain more moisture, producing a line of lusher, taller crops; a buried wall does the opposite. Seen from the air at the right time of year, these subtle differences in growth resolve into shapes that are invisible to anyone standing in the field itself. The circular form identified at Rathkennan is consistent with the kind of enclosed settlement that was common throughout early medieval Ireland, though without excavation the date and function of this particular site remain open questions. A second possible enclosure was identified on the same aerial photograph roughly 60 metres downslope to the south-west, hinting that this patch of Tipperary hillside may have supported more activity in the past than its present agricultural appearance suggests.