No stone marks the spot, no interpretive panel, no hollow in the ground. The only evidence is cartographic, a mark on a specialist map produced in 1978 by the Friends of Medieval Dublin, a group whose work did much to document the buried and forgotten layers of the city's mediaeval infrastructure.

The Friends of Medieval Dublin Map, compiled in 1978, places the mill specifically within the lower yard of the castle complex, the area that today functions largely as a public thoroughfare and event space. The reference was picked up by Bradley and King in 1987, where it appears catalogued as entry number 208, a dry but significant acknowledgement that this was considered a genuine site worth recording. Mills in mediaeval urban settings were not incidental features. They were essential economic infrastructure, typically driven by water diverted from a nearby source, and their placement within or adjacent to a castle precinct would have served the garrison and the wider administrative apparatus that Dublin Castle housed. The River Poddle, which once ran close to this area and was extensively managed and channelled throughout the mediaeval period, is the most likely candidate for whatever watercourse would have powered such a structure.

There is, as the record puts it plainly, no visible surface trace. A visitor standing in the lower yard today will find nothing that announces the mill's former presence. What makes the site worth knowing about is precisely that absence, the way it illustrates how much of mediaeval Dublin exists only in documents, maps, and catalogues rather than in anything you can point to or photograph. If you are in the castle complex and curious, the lower yard is freely accessible during opening hours. The value here is not in what you see but in knowing what the ground might conceal, and in understanding that the 1978 map, unglamorous as it sounds, represents a serious effort to record a city that was, for a long time, poorly served by its own historical memory.