What survives, barely, is the ghost of a head race, the channel that fed water to the wheel, traced by two roughly parallel earthen banks running downhill for around 150 metres on a north-north-west to south-south-east axis, converging as they go. A stream once emerged from the fosse, the defensive ditch surrounding the enclosure, passed beneath a small bridge just outside it, and then travelled between those banks to drive the mill below. The geometry of it is still legible on a 1933 Ordnance Survey map, even if the landscape itself has largely swallowed the evidence.

The mill was identified as possibly of the horizontal type, a form of watermill in which the wheel lies flat in the water rather than standing upright, allowing it to be driven directly by the current without the need for gearing. This older, simpler technology was once widespread in Ireland and is associated with early medieval milling. Its positioning immediately beside an ecclesiastical enclosure is telling; early Irish monasteries and church settlements commonly controlled milling operations, which were both economically and socially significant in the surrounding community. The scholar E. Rynne suggested the horizontal-wheel identification, and the combination of the earthworks and stream course on the 1933 map supports the reading of those parallel banks as a mill head race. Aerial photography taken in July 1970 shows the features still reasonably intact at that point, but subsequent decades have reduced what was visible to only faint surface traces.