These sites, which appear across Ireland in their thousands, are among the most common prehistoric monuments in the country, yet they remain quietly puzzling. The leading interpretation is that they functioned as outdoor cooking places, where stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, cracking in the process and building up over time into the characteristic mounds of fire-shattered rock that survive today. Marshy, waterlogged ground was favoured, since a ready water supply was essential to the whole operation.

By the time the Ordnance Survey mapped this part of Cork in 1842, the site was already visible as a horseshoe-shaped mound, that curved outline being the signature form of a fulacht fia, shaped by the gradual accumulation of discarded burnt material around three sides of a central working area. The horseshoe plan recorded on the six-inch map suggests the mound was reasonably well preserved at that point. Most fulachtaí fia in Ireland date to the Bronze Age, broadly speaking the period from around 2000 to 500 BC, though some sites have produced earlier or later dates. No excavation details are recorded for the Ballynamaddree example, so its precise date and any finer details of its use remain open questions.