The stone facing is subtle enough that most people passing along this part of the river would give it no particular attention, yet its profile in the channel suggests the former presence of a vertical mill wheel, the kind that turns on a horizontal axle driven directly by the flow of water against its paddles or buckets.

The mill's history reaches back at least to the mid-seventeenth century. The Civil Survey of 1654 to 1656, a detailed post-Cromwellian record of Irish landholding and property, lists among Kilkenny's corn mills one described as 'standing upon Grenes Bridge', with the Bishop of Ossory and others named as tenants at the time the town was taken in 1650. John Rocque's map of 1758 shows the mill sitting immediately south of a medieval bridge that no longer exists in that form. That bridge, known as the old Green's Bridge, was destroyed in a great flood in 1764, though one of its arches survived and still spans the upper mill stream today. The mill shown on Rocque's map stood beside this surviving arch, and the site is now roughly fifty metres south of the present Green's Bridge, which replaced the earlier structure. There is also a possibility, noted by local historian Doyle, that this mill may have been the original mill associated with St. John's Priory, a medieval Augustinian house in the city, though the connection remains tentative.