The term refers to a type of prehistoric cooking site found in enormous numbers across Ireland, typically consisting of a trough, a hearth, and a mound of fire-cracked stone that accumulated as heated rocks were dropped into water to bring it to the boil. They are among the most commonly recorded prehistoric monuments on the island, yet each individual example tends to attract little attention, quietly surviving as low mounds in pasture or, as here, as scorched patches revealed only when a field is turned.

What makes the Castlemary site particularly interesting is that it does not stand alone. It belongs to a cluster of five fulachta fiadh recorded in close proximity to one another, a concentration that suggests sustained or repeated activity in this part of east Cork over prehistoric time. The burnt spread at Castlemary was noted by P. Lyons and is one of several such monuments in the immediate area, catalogued together as a group. Clusters of this kind are not unusual in the Irish archaeological record, and they raise questions about whether such sites were used seasonally, whether they served communities returning to a favoured location, or whether they reflect some other pattern of land use that is now difficult to read.