That opening, set low in the wall, is where the shaft of a mill wheel once turned. The watercourse itself, likely modified at some point to serve as a millrace, a channel engineered to direct water onto a mill wheel with enough force to drive the grinding machinery, has been dry for generations. The building was eventually converted into a dwelling house, though it is now partly roofless, and its domestic incarnation did little to disguise the proportions that betray its original purpose: it is notably narrow and lower than you would expect of a standard two-storey house, built to the logic of industry rather than comfort.

The mill probably dates from the sixteenth century, and by 1640 it was recorded as a functioning concern. The Down Survey, a remarkable mid-seventeenth-century mapping project that documented land ownership across Ireland in the years following the Cromwellian conquest, marks a mill in Maddockstown on both its barony map of Gowran and its parish map of Blackrath and St Martins. The accompanying terrier, a written inventory that accompanied the survey maps, notes "a Mill in repaire" on Maddockstown and identifies Sir Edmund Blanchfield as the proprietor in 1640. The Blanchfields were a Kilkenny Anglo-Norman family with deep roots in the county, and the mill's presence on their lands at that date suggests it was already an established part of the local agricultural economy well before the surveyors arrived to record it.