It follows a deliberate path: out of St Patrick's holy well, along an overflow channel, and into a small circular stone trough barely half a metre across. One side of the trough's rim has been broken, or perhaps shaped, lower than the rest, allowing the water to spill out at a controlled point and continue its course towards a stream running roughly north-north-west to south-south-east. It is a modest piece of engineering, but it suggests that whoever shaped this basin was thinking carefully about where the water went after it left the sacred source.

Holy wells dedicated to St Patrick are found across Ireland, and many accumulated small associated structures over centuries, from stone basins and bullaun stones (natural or worked boulders with hollowed depressions, often used to collect water) to enclosing walls and tended planting. This trough, externally about 54 centimetres in diameter and 35 centimetres tall, with an internal depth of 25 centimetres, is plain and functional rather than decorative. Its relationship to the well is hydraulic as much as devotional: it manages the flow. The broken rim acts as a weir, ensuring overflow leaves at one specific point rather than spreading. Whether the trough was cut to serve a practical purpose from the outset, or whether it also held some ritual significance as part of the well complex, the stonework connects it unmistakably to the wider site.