Stretching seventeen metres across and rising at its highest points to just under half a metre, it is composed almost entirely of burnt material, the characteristic dark, fire-cracked residue that identifies a fulacht fia. The mound is uneven, peaking in three distinct places before flattening out elsewhere, giving it a gentle, irregular profile against the ground.

A fulacht fia is a type of prehistoric cooking site found in enormous numbers across Ireland, typically consisting of a trough, a hearth, and a mound of shattered stones. The stones would be heated in the fire and then dropped into a water-filled trough to bring it to the boil; after repeated use they cracked and became useless, and were discarded into the growing mound nearby. The Caherbarnagh example is unremarkable in this basic mechanism, but its setting adds a layer of quiet interest. It lies approximately fifty metres south-south-east of a second fulacht fia, meaning two of these prehistoric cooking or processing sites were in use within a short distance of one another on the same stretch of ground. Whether they were contemporary or separated by generations is not recorded, but their proximity suggests this part of mid-Cork saw sustained activity during the Bronze Age, when fulachtaí fia were most commonly in use.