Exactly where is no longer known. That uncertainty is itself the most interesting thing about this site: a piece of infrastructure documented in a royal grant four centuries ago, and yet its precise location has never been pinned down.

The earliest firm reference comes from 1612, when a man named Thomas Petyt of Irishtown received a grant that listed his holdings at Killpatrick as comprising a castle, a bawn, and a watermill. A bawn, in the terminology of the period, was a walled or fortified enclosure attached to a tower house or castle, used to protect livestock and provide a defensible outer yard. The three elements together, castle, bawn, and mill, suggest a working estate of some consequence. The grant appears in the Calendar of Patent Rolls of Ireland for the reign of James I, placing it squarely in the plantation era, when the Crown was actively redistributing land across the midlands and formalising ownership through exactly this kind of documented conveyance. By 1837, when the Ordnance Survey produced its first detailed six-inch maps of Ireland, a corn mill was marked in the townland. Whether that nineteenth-century mill occupied the same ground as the one Petyt held in 1612 is unconfirmed, though the possibility is a reasonable one: mill sites tend to persist wherever water and gradient allow, and later industrial buildings frequently rose on older foundations.