It measures roughly eighteen metres from north to south and eleven metres across, rising only about twenty centimetres above the surrounding ground. Easy to plough around, easy to overlook, it is the kind of feature that a casual walker might take for a slight rise in the terrain.

This is a fulacht fia, one of the most common prehistoric monument types in Ireland and yet still somewhat mysterious in terms of its precise function. The term refers to a crescent or horseshoe-shaped mound composed largely of fire-cracked stone, the accumulated debris of repeated heating. The broadly accepted interpretation is that these sites were used for cooking, with stones heated in a fire and then dropped into a water-filled trough to bring it to the boil, though some researchers have proposed uses ranging from textile processing to bathing. The proximity of this example to a stream fits a well-established pattern; nearly every fulacht fia is found close to a water source, which would have been essential to whatever activity took place there. Most date to the Bronze Age, roughly 1500 to 500 BC, though some have produced earlier dates. The Knockcloona example sits in tillage ground, which means centuries of agricultural activity have been taking place around and possibly across it, making the survival of even a shallow mound something worth noting.