It measures roughly fourteen metres by ten, rising less than a metre above the surrounding ground, and it is composed almost entirely of burnt and fire-cracked stone. This is a fulacht fia, a type of prehistoric cooking or processing site found in great numbers across Ireland, typically Bronze Age in date. What makes the Lackendarragh example quietly worth noting is its company: a second fulacht fia lies just two metres to the south-west, the two monuments almost touching.

A fulacht fia, sometimes called a burnt mound, generally consists of the accumulated debris from a simple but effective technology. A trough, usually dug into the ground near a water source, was filled with water, and stones heated in a nearby fire were then dropped in to bring the water to a boil. The shattered, heat-spent stones were raked aside after each use, and over generations this discard built up into the low, horseshoe-shaped or oval mound that survives today. The proximity of both mounds at Lackendarragh to a stream fits the pattern well; reliable water was essential. Whether the two sites were used simultaneously or represent separate episodes of activity across many generations is impossible to say without excavation, but their closeness suggests this particular spot, beside this particular watercourse, was returned to more than once.