A substantial subcircular enclosure at Ballyla, measuring roughly 100 metres north to south and 85 metres east to west, leaves no visible trace on the ground but shows up clearly as a cropmark when viewed on satellite imagery. Cropmarks appear when buried features such as ditches or banks affect how the vegetation above them grows, producing subtle differences in colour and vigour that become legible from above, particularly in dry summers when crops stress quickly over compacted or disturbed soil. In this case, a single ditch or drain, somewhere between two and five metres wide, traces out the enclosure's boundary against the flat surrounding landscape.

The site was first reported by Jean Charles Cailére, whose observation drew attention to what might otherwise have gone entirely unnoticed. Inside the enclosure, in its north-eastern quarter, a further cropmark indicates a rectangular feature approximately 30 metres east to west and 20 metres north to south, identified as a quarry. That interior detail complicates the picture somewhat. The enclosing ditch may not be the boundary of a settlement or ceremonial space in the conventional sense; one interpretation is that it represents drainage cut around a slightly raised area of ground rather than a deliberately constructed enclosure in the archaeological meaning. The question of what exactly this feature represents remains open, which is itself part of what makes it interesting. A landscape that looks entirely unremarkable at eye level turns out, from above, to contain something that has not yet been fully explained.