There is no river visible, no canal, no feature that immediately accounts for it. The name simply sits there, a quiet label pointing to something that has long since vanished from the surface of the city, yet which once carried water through the urban fabric in a way that shaped everyday life for centuries.

The feature is recorded as 'Watercourse' on the Ordnance Survey six-inch map of 1837, but its origins are considerably older. It appears on the Down Survey map compiled around 1655, the great land survey undertaken after the Cromwellian conquest of Ireland, which makes this watercourse a documented presence in the city for well over three and a half centuries. According to the antiquarian research of P.W. Joyce, writing in 1912, and the earlier work of Henry Berry, published in 1891, this formed part of the Dublin City watercourse that served Deane Street. Urban watercourses of this kind were engineered channels, sometimes open, sometimes partially culverted, that drew water from streams or springs and directed it to where the population needed it, supplying mills, tanneries, households, and public conduits. They were the arteries of pre-modern urban infrastructure, and they tended to disappear gradually as cities expanded, piped water arrived, and the ground was built over and built up again.

There is no dramatic physical remains to seek out here, and that is rather the point. What a visitor can do is walk the area with the 1837 OS six-inch map, freely available through the Historic Environment Viewer and similar online resources, and trace how the street pattern and placenames still carry the ghost of the old channel. Comparing historic and modern mapping often reveals how much of the old city is encoded in the layout of lanes and boundaries that look, on the ground, entirely unremarkable. The name 'Watercourse' itself, surviving into the present day on local maps and records, is the most durable evidence of what once ran here.