It measures roughly eight metres east to west and four metres north to south, rising to just 0.7 metres at its highest point, with an opening 1.7 metres wide facing east. Unassuming as it is, it represents one of the most common and most debated monument types in the Irish archaeological landscape.

This is a fulacht fia, a category of prehistoric cooking site found in enormous numbers across Ireland, with particularly dense concentrations in Munster. The typical form involves a trough dug into the ground, usually near a water source, into which stones were heated in a fire and then dropped to bring the water to a boil. The discarded, fire-cracked stones accumulated over time into the characteristic mound that survives today, its burnt and shattered material giving it a distinctively dark, crumbly texture. The horseshoe or kidney shape is a direct result of this process, the trough sitting at the open centre while spent stone built up on three sides. Most fulachta fia date to the Bronze Age, roughly 1500 to 500 BC, though some examples span a wider range. The one at Knockyrourke conforms closely to this familiar pattern, its eastward-facing opening consistent with examples recorded across the county.