It is not much to look at, but it represents one of the most common and still not fully understood monument types in the Irish landscape: the fulacht fia.

A fulacht fia, sometimes called a burnt mound, is thought to be a prehistoric cooking site. The typical interpretation is that stones were heated in a fire and then dropped into a water-filled trough to bring the water to a boil, and that meat was cooked in this way. Over time, the repeated heating and quenching cracked the stones into fragments, and these were raked out and discarded nearby, gradually building up the characteristic mound of shattered, fire-reddened material that survives today. Other theories have proposed uses ranging from textile processing to bathing. Ireland has thousands of these sites, dating broadly to the Bronze Age, and they tend to cluster near streams or boggy ground where water was readily available. What makes the Glenleigh example quietly striking is its company: two further fulachta fiadh lie within fifty metres, one approximately thirty metres to the north-east and another roughly fifty metres to the south-east. Whether this reflects repeated use of a favoured spot over generations, or something more organised about the way this particular hillside was used, is the kind of question that the mounds themselves cannot easily answer.