To an untrained eye it might pass for a natural rise in the ground, or perhaps the remnant of some collapsed field boundary. In fact it belongs to a class of monument that turns up with quiet regularity across the Irish landscape, and whose everyday purpose still prompts debate among archaeologists.

Burnt mounds, sometimes called fulachta fiadh in the Irish tradition, are generally understood to be the accumulated debris of a cooking or heating method that involved dropping fire-heated stones into a water-filled trough. The stones crack and shatter with repeated use and cannot be reused indefinitely, so they are discarded nearby, building up over time into the characteristic low mounds of scorched and fragmented rock that survive today. Most date to the Bronze Age, roughly 2000 to 500 BC, though examples from other periods are known. The Lissooleen mound was recorded by Michael Connolly during a survey of the Lee Valley area carried out in 1996 and 1997, at which point it measured approximately seven metres north to south, eight metres east to west, and stood just fifty centimetres above the surrounding ground.