Beneath the ploughed surface lay two distinct spreads of burnt stone, sitting roughly 30 metres to the south-east of yet another similar spread, suggesting this particular stretch of north Tipperary was once a site of repeated, deliberate activity stretching back thousands of years.

What Hughes and O'Brien identified in 1999 are the likely remains of a fulacht fia, a type of prehistoric burnt mound found in great numbers across Ireland and Britain. The term refers to a low, characteristically horseshoe-shaped mound formed from the accumulated debris of repeated heating and cooling of stones, which were used to boil water in a nearby trough. The stones crack and shatter with use and become useless, so they were discarded into a steadily growing heap. At Tullahedy, the two burnt stone spreads together measure approximately 9 metres by 16 metres, and their arrangement suggests they may represent the collapsed or ploughed-out remnants of one such classic horseshoe mound. The find sits within a broader landscape that appears to have been visited and revisited for the same purpose, given the proximity of the neighbouring burnt spread just 30 metres away.