It measures around twelve metres north to south and thirteen metres east to west, and it gives nothing away to a casual eye. The site is only clearly legible from above, where it registers as a soilmark in aerial photography.

The feature belongs to a class of monument known as a fulacht fia, the most common prehistoric archaeological site type found in Ireland. The basic principle was straightforward: a pit was dug, often lined, and filled with water; stones were heated in a nearby fire and dropped into the pit to bring the water to a boil. Over repeated use, those stones cracked and became useless, and the discarded fragments built up into a horseshoe-shaped mound surrounding the pit. It is this accumulation of fire-cracked, burnt stone that survives at Killinane, now grass-covered and settled into the pasture. Thousands of fulachta fia are known across Ireland, particularly in low-lying or marshy ground near water sources, though their precise range of uses, cooking being the most widely accepted, has been the subject of considerable archaeological discussion.