The stream is gone now, reduced to a dry channel in the landscape, but the mound remains: roughly subcircular, stretching sixteen metres north to south and eighteen metres east to west, rising to about a metre and a quarter in height. It is made almost entirely of burnt stone and charcoal-blackened earth, the kind of debris that accumulates not from habitation but from repeated, intensive heating. This is a fulacht fia, one of the most common prehistoric monument types in Ireland, and yet one of the least immediately legible to a passing eye.

A fulacht fia is essentially the remains of an ancient cooking or heating site. The typical method involved heating stones in a fire and then dropping them into a water-filled trough to bring the water to a boil. The stones, repeatedly thermal-shocked, eventually cracked and became useless, and were raked out and discarded nearby. Over centuries of repeated use, those discarded stones accumulated into the characteristic mound seen today. The proximity to a water source was not incidental: a reliable supply was essential to the whole operation, which explains why these monuments cluster near rivers, streams, and boggy ground. Here at Curraghoo Beg, the dried-up stream bed to the south-east tells its own story, marking where that water supply once ran. Most fulachtaí fia date to the Bronze Age, roughly between 2000 and 500 BC, though the exact period of use at any individual site is rarely easy to determine without excavation.