It is not. The mound is made up of heat-shattered stones and charcoal-dark soil, the debris of repeated, deliberate burning, and it belongs to a category of prehistoric monument found across Ireland and Britain known as a burnt mound.

Burnt mounds, or fulachtaí fia as they are known in Irish, are among the most common archaeological features in the Irish landscape, yet they remain poorly understood. The prevailing theory is that they were used for cooking, most likely by heating stones in a fire and dropping them into a water-filled trough to bring it to a boil. The discarded, cracked stones accumulated over time into the distinctive mounds we see today. Some researchers have suggested additional or alternative uses, including bathing, brewing, or textile processing, though none of these ideas has been conclusively settled. The mound at Derreenataggart sits on a level shelf of rough hill pasture, a position that would have offered reasonable access to water running off the mountain slopes. It measures roughly six metres along its longer north-east to south-west axis, four and a half metres across, and rises only about thirty-five centimetres above the surrounding ground, making it a modest example, though its oval form is well defined.