It measures roughly 8.8 metres along its longer axis and rises to about a metre in height, and where erosion has worn away its northwest arm, the dark burnt material packed inside is exposed to the open air. That blackened fill is the giveaway: this is a fulacht fia, one of Ireland's most commonly encountered prehistoric monuments and one of its least understood.

A fulacht fia, sometimes called a burnt mound, is the accumulated debris of a cooking or heating process practised widely across Bronze Age Ireland. The typical method involved heating stones in a fire and dropping them into a water-filled trough to bring it to boiling point; the cracked, fire-shattered stones were then raked out and discarded, gradually building up the characteristic horseshoe or crescent shape around the trough's edge. The opening of the Drombohilly mound, measuring around 3.6 metres across, faces southwest towards a wet area, which would have provided a reliable water source. What is particularly striking about this site is that it does not stand alone. A second fulacht fia lies approximately 35 metres to the southeast, and a possible third sits around 150 metres further south. Clusters like this are known elsewhere in Ireland, though the reasons for repeated activity in one area remain a matter of debate, with theories ranging from communal feasting to hide-working or even bathing.