It appears in medieval Crown records, it surfaces again in an eighteenth-century antiquarian's notebook, and then it dissolves back into the landscape, its precise location still unresolved. That combination of documentary presence and physical absence makes it one of the more quietly interesting puzzles in the area.

The mill was associated with the Royal manor of Saggart, known in Irish as Teach Sagard, a medieval administrative centre held by the Crown in the area south-west of Dublin. In 1337, Edward III granted his yeoman Henry de Stone the use of a carucate of land, a unit of medieval land measurement roughly equivalent to what one plough team could work in a year, along with the mills of Tassagrade, as Saggart was then recorded, and of Milton, which corresponds to Milltown. The grant ran for ten years at a yearly rent paid to the Exchequer of Dublin. The arrangement was practical and formal; mills were valuable assets, essential for grinding grain, and attaching them to a royal manor meant they could be leased for reliable income. The same mill, or very likely the same one, appears again in 1780, when the antiquarian Austin Cooper noted a mill near the castle during one of his tours of the Dublin countryside. His observation is recorded by Liam Price in his work on the area, published in 1942.

Because the exact location of the mill within the townland has not been established, there is no specific ruin or site to visit. What the area does offer, for anyone drawn by the documentary trail, is a walk through a townland with a genuinely layered medieval past, where the castle Cooper would have known once stood and where the general lie of the land, the streams and low ground that would have powered a millwheel, still shapes the landscape. Anyone with an interest in medieval land use or in the practical infrastructure of Crown manors in the Dublin hinterland will find the broader Saggart area worth slow attention, even if the mill itself remains stubbornly off the map.