It measures roughly twenty-two metres north to south and fourteen metres east to west, rising only about a quarter of a metre above the surface, easily mistaken for a natural feature or an odd patch of disturbed earth. A drain cut into the western side exposes the interior, where burnt material extends to a depth of one and a half metres, suggesting a considerable accumulation of activity below what the eye can immediately see.

This is a fulacht fia, a type of ancient cooking site found in large numbers across Ireland, typically dating from the Bronze Age, though many continued in use into later periods. The working principle was straightforward: stones were heated in a fire and then dropped into a water-filled trough to bring the water to a boil. Over repeated use, the stones cracked and became useless, and the discarded fragments built up into the characteristic horseshoe-shaped mound that survives today. The location at Knockbarry follows a pattern familiar from such sites elsewhere: a stream curves around the western and southern sides, ensuring a reliable water supply close at hand. What makes the Knockbarry site a little unusual is that it does not sit in isolation. A second fulacht fia lies approximately a hundred and twenty metres to the south-south-east, raising the question of whether the two were in use simultaneously, serving a larger community or a more intensive level of activity, or whether one simply succeeded the other across a span of generations.