It measures ten metres long, seven and a half metres wide, and rises just sixty-five centimetres from the ground, its opening facing south-west. It is, in other words, easy to miss. But this modest hump is a fulacht fia, one of the most common and yet persistently puzzling monument types in the Irish landscape.

A fulacht fia, sometimes called a burnt mound, is the accumulated debris of a cooking method used widely in prehistoric Ireland. The typical arrangement involved a trough, usually timber-lined or stone-lined, filled with water, into which heated stones were dropped to bring the water to a boil. The stones would crack and shatter with repeated use, and the fragments were piled to the side, forming over time the horseshoe or kidney-shaped mounds that survive today. The Glenleigh example follows this classic form closely. What makes the site quietly interesting beyond its own dimensions is that a second fulacht fia lies roughly a hundred metres to the south-east, suggesting this particular patch of mid-Cork was a place of repeated, perhaps sustained, activity rather than a single episode of use. Whether the two sites were contemporary with one another or separated by generations is not something the ground surface alone can answer.