Nothing of it remains above ground, yet the dimensions recorded in a survey of 1585 suggest something rather solid and deliberate: a building roughly 32.5 metres long, with walls 1.25 metres thick and nearly 6 metres high. Those are not the proportions of a modest townhouse. They belong to something built to last, and built with some awareness of its position on the water.

The structure is associated with the Ussher family in the sixteenth century, a name that recurs in the civic and ecclesiastical life of early modern Dublin. The survey that preserved its measurements was carried out in 1585 by Perrot, and the historian J.W. de Courcy drew attention to it in his 1996 study of the Liffey. What makes the site older still is the documentary trail running beneath even that. A house on what appears to be the same ground was granted in 1284 to a Robert de Notyngham, and then recorded again in 1317 when a John de Grauntsete restored it. The medieval habit of rebuilding on an existing footprint means that what the Ussher family occupied in the 1500s may have continued a line of occupation stretching back more than two centuries before them, all of it pressed against the same riverbank.

There is no surviving physical trace, and a visitor standing near Father Mathew Bridge today will find nothing to mark the spot. The bridge itself, crossing the Liffey at Church Street, gives a reasonable sense of the general location, with the site lying to the west on the south bank. The interest here is less visual than conceptual: a layered sequence of occupation, grant, ruin, and rebuilding, now entirely absorbed into the city fabric. For anyone tracing the medieval street pattern of Dublin along the Liffey's edge, the absence itself is worth pausing over.