The site is a fulacht fia, a type of ancient cooking place found across Ireland in great numbers, typically recognised by a horseshoe-shaped mound of heat-shattered stone left behind after centuries of use. The principle was straightforward: stones were heated in a fire and dropped into a water-filled trough to bring it to boiling point, and the cracked, discarded stones slowly built up into the distinctive mound that survives today. At Clashnasmut, even that mound had vanished beneath the landscape.

The site was identified by a researcher named Will Forbes, but when it was visited in 2002 the ground gave nothing away. The river bank had been colonised by dense scrub and clumps of gorse, obscuring whatever surface traces might otherwise have indicated prehistoric activity. Fulachtaí fia, which date most commonly to the Bronze Age, are generally associated with low-lying, waterlogged ground near streams or rivers, which makes the setting here entirely typical, even if the degree of concealment is notable. The Lingaun River runs through a quiet stretch of south Tipperary, and the tributary stream beside which this site sits would have offered exactly the reliable water source these cooking places required.