It is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, typically Bronze Age in origin. The name, roughly meaning "cooking place of the deer" in older Irish, refers to a recurring arrangement: a trough filled with water, heated by dropping fire-cracked stones into it until it boiled, used to cook meat or possibly for other communal purposes. The stones, shattered by repeated heating and cooling, were raked out after use and piled nearby. Over centuries of use and abandonment, those discarded stones accumulated into the low, crescent-shaped or oval mounds that archaeologists now find scattered across Irish farmland.

The Knockearagh example measures roughly 14.4 metres on its longer north-northwest to south-southeast axis and 13.7 metres across, rising only about 0.3 metres above the surrounding ground. The surface of the mound carries several depressions, which is characteristic of these sites, the result of slumping and settling in the burnt and broken stone over time. One detail worth noting is that burnt material from the mound has been incorporated into the adjacent field fence, meaning some portion of the archaeological deposit was disturbed or quarried at some point, likely when a farmer was simply looking for ready material to build a boundary. The mound sits about 50 metres southwest of a well, a proximity that is not accidental. Fulachtaí fia are almost always found close to water sources, whether natural springs, streams, or wells, since a reliable water supply was essential to the whole process.