It measures roughly nineteen and a half metres in each direction and rises about a metre above the surrounding ground. To the untrained eye it looks like a natural hump in a wet field. In fact it is a fulacht fia, one of the most common yet consistently overlooked monument types in the Irish landscape.

A fulacht fia is a Bronze Age cooking site, typically consisting of a horseshoe-shaped mound of burnt and shattered stone built up around a trough dug into the ground. The method was simple but effective: stones were heated in a fire, then dropped into a water-filled trough to bring it to a boil, cooking meat or, as some researchers have proposed, serving other communal purposes such as brewing or textile preparation. The discarded, heat-shattered stones accumulated over repeated use into the characteristic mound that survives today. Thousands of these sites are known across Ireland, and they cluster particularly in low-lying, waterlogged ground near streams, exactly the kind of setting found at Shanavally. The proximity to running water was practical rather than incidental; the trough needed a reliable source, and marshy ground meant it stayed filled. The overgrown condition of the Shanavally mound is typical: centuries of vegetation have softened its outline, and without knowing what to look for the subtle rise of burnt stone can easily read as ordinary topography.