It measures roughly thirteen metres east to west and just over nine metres north to south, rising only about forty centimetres from the ground. Easy to walk past, easy to mistake for a natural rise in the field. It is, in fact, the remains of a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, and one of the most common archaeological monument types in the country.

A fulacht fia typically consists of a mound of fire-cracked stone and charcoal built up over many uses, usually positioned close to a water source. The working method, as understood from excavated examples elsewhere, involved heating stones in a fire and then dropping them into a water-filled trough to bring the water to a boil, after which meat could be cooked. The discarded, shattered stones accumulated into the characteristic horseshoe or D-shaped mounds that survive today. The Ballygrace example follows that pattern closely, positioned immediately beside a stream that would have supplied the necessary water. Most fulachtaí fia date to the Bronze Age, roughly 1500 to 500 BC, though some have produced dates outside that range. The mound here has not escaped the ordinary pressures of farmland use, with cattle having disturbed and compressed its surface over time, a common fate for low earthworks in working pasture.