It measures roughly fourteen and a half metres long, nine metres wide, and just over half a metre high, its oval profile now partially softened by vegetation. To the uninitiated it might look like nothing more than a slight rise in a wet field, but it is a fulacht fia, one of the most common prehistoric monument types in Ireland, and one of the most persistently mysterious.

A fulacht fia, sometimes called a burnt mound, is essentially the spoil heap left behind by repeated cycles of heating stones in a fire and dropping them into a water-filled trough to bring the water to the boil. The process is simple and effective, and these sites cluster near water sources almost without exception, which makes the streams flanking this one entirely typical. What they were used for is less settled: cooking meat is the traditional explanation, but researchers have also proposed brewing, hide-working, bathing, and textile processing. The mounds themselves are the accumulated debris of shattered, heat-stressed stone, discarded after each use. Bronze Age in date for the most part, they represent a technology that was apparently repeated across this landscape with some regularity. A second fulacht fia lies roughly a hundred metres to the west of this one, suggesting that this particular stretch of marshy ground near Pluckanes was returned to, possibly across generations, for whatever purpose these features served.