It is a fulacht fia, a type of monument found in considerable numbers across Ireland, typically consisting of a horseshoe-shaped mound of burnt and shattered stone beside a trough that would once have been filled with water. The working theory, supported by experimental archaeology, is that these were ancient cooking sites: stones were heated in a fire, dropped into the water-filled trough to bring it to a boil, and used to cook meat. Some researchers have proposed other uses, including textile processing or bathing, though the cooking explanation remains the most widely accepted. Whatever their purpose, fulachtaí fia date mainly from the Bronze Age, and this one on Ballylin Hill sits quietly in that same deep prehistory.

The site was identified in 1986 by Jerry McMahon of Ardagh, a member of the Newcastle Historical Society, during a field trip to the nearby Ballylin hillfort, whose external rampart lies roughly 330 metres to the north-west. The proximity of the two monuments is notable; hillfort and fulacht fia occupying the same landscape suggests a period of sustained activity on and around this hill. A second fulacht fia lies approximately 60 metres to the south-east, in dense woodland, and it is that site which has been excavated. Radiocarbon dating placed it firmly in the Middle Bronze Age, returning a date of around 3,400 years before present, with a margin of plus or minus 60 years, a result published by Brindley and colleagues in 1989 to 1990. The precise location of the pasture site recorded by McMahon rests on local knowledge rather than surveyed coordinates, and its general position only became discernible on a Google Earth image taken in April 2015.

Accessing this part of County Limerick requires some patience. The site sits on rough pasture on the hill's eastern slope, and the surrounding area includes dense woodland that obscures the nearby fulacht fia to the south-east. Anyone seriously interested in the monument would do well to consult the SMR file record and the location map prepared by Jerry McMahon, as the exact position relies on local information rather than fixed mapping. The ground will be easier to read in late winter or early spring, before vegetation thickens. The hillfort rampart to the north-west offers its own reward for those willing to take the longer view across the landscape.