The name, loosely translated from Irish, means something like "cooking place of the deer," and the monuments typically appear as horseshoe-shaped or kidney-shaped mounds of fire-cracked stone, usually found close to a water source. The working theory, supported by experimental archaeology, is that Bronze Age people used them to heat water: stones were fired in a nearby hearth, then dropped into a water-filled trough, bringing the contents rapidly to a boil. What exactly was being cooked, or whether cooking was even the primary purpose, remains open. Some researchers have proposed uses ranging from textile processing to sweat-house bathing.

Fulachtaí fia are predominantly associated with the Bronze Age, roughly 2000 to 500 BC, and Ireland has one of the densest concentrations of them anywhere in Europe, with estimates running to several thousand recorded examples. Clare is reasonably well populated with them, and the Ballymaley site adds to that county's prehistoric record. The mounds themselves are largely composed of the shattered stones that accumulated over repeated use, since the thermal shock of plunging hot rock into cold water causes the stone to crack and eventually become useless for further heating. Over time, this refuse built up into the low, distinctive humps that survive in fields and bogland today, often preserved precisely because the waterlogged ground around them discouraged later disturbance.