The slight rise at the centre, barely perceptible underfoot, is the only hint that something lies beneath. What it conceals is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, and one of the most quietly abundant monuments in the Irish landscape.

Fulachtaí fia, the plural form, are typically dated to the Bronze Age, roughly 2000 to 500 BC, though some examples fall outside that range. The name, loosely translated as "cooking pit of the deer" or sometimes associated with wandering hunters in early Irish literature, describes a remarkably consistent technology: a trough dug into the ground, usually lined with timber or stone, filled with water, and heated by dropping fire-cracked stones into it. The shattered, burnt stone, discarded after use, built up over time into the characteristic horseshoe-shaped mound that survives at thousands of sites today. The Killowen example presents as a grass-covered spread of this burnt material, the accumulated debris of repeated use across what may have been a considerable span of time. Whether the nearby well reflects an ancient association with a water source, or is simply a later, coincidental neighbour, is not recorded.