The site belongs to a class of monument known as a fulacht fia, the most common prehistoric archaeological monument found across Ireland. The term refers to a mound of fire-cracked stone, typically horseshoe-shaped, built up over centuries of repeated use around a trough, into which heated stones were dropped to boil water for cooking. They are found in their thousands across the Irish landscape, usually in low-lying or waterlogged ground, and date predominantly from the Bronze Age, roughly 2000 to 500 BC.

At Knocknakilla, the site left no visible surface trace by the time it was formally recorded, but its existence was preserved through the account of people working the land. Around 1968, when the field was being reclaimed for pasture, burnt material came to light, the characteristic dark, charcoal-flecked, heat-shattered stone that typically marks a fulacht fia. That informal record was enough to place the site in the county inventory. What makes the location slightly more remarkable is that the same field contains a second monument of the same type, recorded separately, along with a further possible fulacht fia nearby. The clustering of these sites in one area is consistent with broader patterns seen elsewhere in Ireland, where suitable ground near water sources attracted repeated use across generations.