It is easy to overlook, but the darker soil that distinguishes it from the surrounding field, and the fire-cracked stones buried within it, point to something far older than the landscape around it suggests. This is a fulacht fia, a type of prehistoric cooking site found in considerable numbers across Ireland, typically identified by the characteristic crescent or horseshoe of heat-shattered stone that accumulates beside a water trough when rocks are repeatedly heated and plunged into water to bring it to the boil.

The site at Ballylinnen was recorded by Prendergast in 1977. The mound material is distributed across two distinct accumulations, one to the north measuring roughly 8 metres by 12 metres, and a larger one to the south at approximately 12 metres square, with both spreading downslope where they meet on the eastern side. Between them lies the trough itself, roughly 3 metres by 4 metres, where water would once have been heated. The western end of the horseshoe is formed not by accumulated material but by the natural gradient of the hillside, a reminder that whoever chose this location was working with the contours of the land rather than against them. A spring almost certainly supplied the water, though it has since dried up; the trace of an old channel running eastward downslope from the site still hints at how water once moved through this spot. No charcoal was visible in the small area examined beneath the sod, though the fire-cracked stones alone are evidence enough of sustained, repeated burning over what may have been a very long period of prehistoric use.

The views from the site open widely to the north, east, and south, with the hill crest blocking the outlook to the west. It sits in working farmland, and the mound, though low, remains legible in the field, particularly where the darker soil separates it from the pasture around it.