It has not been excavated, and its precise nature remains unconfirmed, but the evidence gathered so far points to the possibility of a fulacht fia, one of the most common yet persistently mysterious monument types in the Irish archaeological record.

A fulacht fia, sometimes called a burnt mound, is essentially a prehistoric cooking or heating site. The typical arrangement involves a trough, usually timber-lined or stone-lined and filled with water, into which fire-heated stones were dropped to bring the water to a boil. The shattered, fire-cracked stones were then discarded into a mound nearby, which is what tends to survive. These sites date mostly to the Bronze Age, though they span a considerable range, and they appear in enormous numbers across Ireland, often in low-lying or waterlogged ground near streams. In 2020, a magnetic gradiometer survey, a non-invasive technique that maps variations in soil magnetism caused by buried features or burning, was carried out over an extensive area at Raheenduff. The survey, referenced in the work of Nicholls that same year, identified a circular feature approximately ten metres in diameter producing a strong magnetic signal consistent with the kind of intense, repeated burning associated with fulacht fia activity. The valley setting fits the pattern well; such monuments are frequently found in sheltered, damp ground where water would have been readily available.