The junction of Exchange Court and Cork Hill, a stone's throw from Dublin Castle, gives no indication that it was once the site of an industrial operation fed by the River Poddle, a watercourse that powered much of the medieval city's grain-milling before being gradually culverted and forgotten over the centuries.

The mill's origins reach back to the late twelfth century, when John, Lord of Ireland, granted the site to a man named William Doubleday, from whom the mills took their name. The arrangement was not straightforward: a half share was held by St Mary's Abbey, the powerful Cistercian monastery on the north side of the Liffey, which had extensive landholdings and commercial interests across the city. The mills sat just outside the town wall, a common position for water-powered mills in medieval urban settlements, since they required access to a reliable watercourse but were often too noisy and fire-prone to be welcomed within the walls themselves. The River Poddle, which ran from its source in Tallaght through the south of the city and joined the Liffey near the present-day Wellington Quay, provided the necessary flow. Scholars Bradley and King, along with a 1978 map of the Fingal and Medieval Dublin project, have helped to fix the location with reasonable confidence at what is now the Cork Hill and Exchange Court junction.

There is nothing to see here in any conventional sense. No stonework, no millrace, no surviving fabric of any kind breaks the surface. The Poddle itself runs entirely underground at this point, as it does along much of its course through the modern city. What the spot offers instead is the particular pleasure of knowing what lies beneath an unremarkable piece of pavement, and of reading the street geography with that knowledge in mind. Cork Hill is walkable from Dame Street, and the area around Dublin Castle sees a steady flow of visitors who pass within metres of the site without any awareness of it. A short detour from the Castle's main entrance is all it takes to stand above where the Doubleday mills once ground grain, channelling a river that the city has long since swallowed whole.