It is easy to overlook, but the care taken in its construction is still visible after centuries: the circular stone-lined depression, roughly 1.8 metres across and 1.7 metres deep, is formed from well-cut stones that fit neatly against one another, suggesting this was not a rough field expedient but a deliberately built piece of agricultural infrastructure.

Corn-drying kilns of this type were a practical necessity in the damp Irish climate, used to dry grain before milling or storage. They typically consisted of a bowl-shaped stone-lined pit where heat was applied, often through a flue or vent, to draw warm air across the grain laid above. At Cahererillan, a possible vent is still visible at the north-north-east side of the structure. The kiln lies to the west of the tower house, itself set within or adjacent to a cashel, a type of stone-walled enclosure characteristic of early and medieval Irish settlement. The collapse of that cashel wall has left the kiln half-buried in debris, its floor now covered with rubble, though its form remains legible. The association of a corn-drying kiln with a tower house and cashel places it within a working agricultural complex, where the grinding and drying of grain would have been as central to daily life as the defensive or residential functions of the larger structures around it.