It measures over fourteen metres in length and rises to a maximum height of 1.4 metres, with a recessed trough area at its open eastern end. This is a fulacht fia, a type of prehistoric cooking site found in considerable numbers across Ireland, typically consisting of a trough that would have been filled with water and heated by dropping fire-cracked stones into it. The discarded, shattered stones accumulate over time into the characteristic mound form that survives today.

The site was first identified by Michael Mahon in 1991, and what makes its position at Formoyle particularly notable is that it does not stand alone. Two further fulachtaí fia lie within a short distance, one roughly twelve metres to the north-north-west and another approximately forty-five metres to the south-south-west. The clustering of three such monuments in close proximity along the same river corridor suggests repeated or sustained use of this part of the landscape over time, rather than a single isolated episode of activity. The Caher River would have provided a ready water source, a practical requirement for any fulacht fia, and the clearing above its bank offered the kind of sheltered, accessible ground that these sites consistently favour.