It measures roughly fifteen metres east to west and fourteen metres north to south, rising to about sixty centimetres at its highest point on the western side. Local knowledge suggests it was once considerably taller, which is not unusual; these features have a long history of being quarried for road fill or simply eroded by centuries of grazing.

The mound is a fulacht fia, a class of monument found in enormous numbers across Ireland, particularly in low-lying or waterlogged ground. The term is sometimes translated loosely as "cooking place of the deer," though the exact original meaning is debated. What the structures represent is clearer: a trough, typically timber-lined or cut into the ground, filled with water, into which fire-heated stones were dropped to bring the water to a boil. The shattered, heat-cracked stones were then raked out and left in a heap beside the trough. Repeated over many seasons or generations, this process built up the characteristic horseshoe-shaped mounds that survive today. Most date to the Bronze Age, broadly between 2000 and 500 BC, though some sites show earlier or later use. The Farrankeal example sits on the southern side of a well that is now drained, a detail that fits the pattern well; fulachta fia are almost always found close to a reliable water source, whether a stream, spring, or, as here, a well.