The French cartographers were not being poetic; there were working water mills here, built out from the city wall just below the Curragower reef, and the name stuck long enough to be recorded. Today, almost nothing of them is visible above ground, yet the evidence for their existence, and for the particular men who owned them, is unusually precise for structures of their age.

The two mills date to the fourteenth or fifteenth century and stood at the western end of Newgate Lane, in the area known as Curragour Castle, wedged between King John's Castle and the medieval quay. A 1590 map held in Trinity College Dublin identifies them as belonging to one Thomas Arthur, and as the "Queen's Mills", and shows them connected to the city wall by a small bridge. The Civil Survey of the mid-seventeenth century described two stone buildings, one measuring roughly 10.8 by 9.1 metres and the other 13.7 by 8.2 metres, each containing mill wheels, along with a thatched house attached to the complex. The second mill is closely associated with a neighbouring structure recorded as the Golding Mill. Together, the pair are thought to correspond to what earlier sources call the King's Mills, suggesting the ownership of these riverside workings passed through several hands across the centuries.

According to researcher Brian Hodkinson, approximately half of one mill building survived into the modern period within the grounds of Limerick's City Hall, where two short stubs of masonry still project out into the river. The City Hall grounds are not always freely accessible, but the riverbank nearby offers a reasonable vantage point, and the Curragower reef itself, a low rocky shelf across the Shannon, remains clearly visible from the path. It is worth pausing at the foot of what was once Newgate Lane and considering that the water rushing over those same rocks once turned wheels inside buildings that straddled the city wall, supplying ground grain to a medieval city that found the spot useful enough to name a whole street after it.