These sites, essentially ancient cooking or processing places, typically consist of a mound of heat-shattered stone alongside a trough that would once have been filled with water and heated by dropping fire-cracked stones into it. They are found in their thousands across Ireland, most dating to the Bronze Age, and they tend to cluster near water, which makes the location here, at the foot of a south-facing slope close to a stream, entirely characteristic.

The spread of burnt material that survives at Knocknacurra is what archaeologists would expect to find where a fulacht fia has been disturbed or reduced over time, particularly on agricultural land. Ploughing scatters and flattens the distinctive mound of cracked, blackened stone that would originally have accumulated beside the cooking trough, leaving the discolouration of the soil as the most legible trace. The south-facing slope and proximity to running water suggest this was a carefully chosen spot, sheltered and reliably supplied, as was typical for whoever used it during the Bronze Age.