The landowner noticed the discolouration while working the land, and it was enough to prompt a closer look. By then, however, ploughing and the planting of barley had done their work, and any surface traces that might once have been visible had been effectively erased.

A fulacht fia is a type of prehistoric cooking site found in considerable numbers across Ireland, typically identified by a horseshoe-shaped mound of fire-cracked and blackened stones surrounding a trough. The standard interpretation is that stones were heated in a fire and then dropped into a water-filled pit to bring it to the boil, used for cooking meat or, as some researchers have suggested, for brewing or bathing. The burnt, shattered stones were raked out and accumulated over time into the characteristic mound. The site at Cankilly sits on a gentle south-facing slope, around seventy metres from a stream, which is precisely the kind of location these sites favour. Proximity to a reliable water source was essential to the process, and low-lying or gently sloping ground near streams accounts for a significant proportion of known examples across the country.

What remains at Cankilly is essentially sub-surface, the dark scorched soil and heat-fractured stones now buried beneath agricultural land. It is the kind of site that exists more fully in the record than on the ground, its presence inferred from a farmer's observation rather than from anything a visitor could now easily read in the landscape.