The name of this mill is now perpetuated as a dwelling in the shadow of Harlech castle, and accessed from FFordd Pen Llech; it is not identified on any of the historic Ordnance Survey maps of the town. But a painting of the castle by Paul Sandby (1731-1809) thought to have been executed c.1779 (The Mills Archive, Reference EMGC-o4-26-44) depicts the mill with water issuing from an opening high on the north-facing wall, clearly from a launder passing over the internal wheel when the wheel was not in use. A photograph made by Miss E M Gardner in 1940 (The Mills Archive, Ref EMGC-04-26-43) shows the mill, a single storey and attic structure built of rubblestone under a pitched slate roof, with a wooden launder sloping at a steep angle into an opening in the south-facing wall; this confirms that the wheel was overshot, and located inside the building at its west end. Sandby's painting shows that the launder would have had a lifting trapdoor to direct water to the wheel, but continued over the wheel when the trap was closed, to discharge water outside the building.

The mill stood at the head of a waterfall skirting the north-east side of the castle rock, and may have been associated with the castle (built 1282-89). The mill building may be incorporated into the present dwelling.
W J Crompton, RCAHMW, 30 May 2019.