Somewhere on or near its precinct stood a gallows, recorded as having been built shortly before 1539, the very year Henry VIII's dissolution of the monasteries was sweeping such establishments from existence across Ireland and England. The coincidence of timing is quietly arresting: a place of religious life erecting an instrument of execution in what turned out to be among its final years.

St Thomas's Abbey had been a significant presence in Dublin since the medieval period, and like many larger monastic houses it held jurisdictional privileges that extended well beyond prayer and charity. The right to maintain a gallows was a mark of what was known as high justice, the authority to try and execute criminals within a defined territory. This was not unusual for powerful ecclesiastical landowners in medieval Ireland, though it sits uneasily beside the devotional purpose of such communities. Howard Clarke, writing in 2002, is the source for the specific detail of the gallows and its construction date, placing it firmly in the historical record rather than local legend. The abbey's dissolution followed shortly after, and the physical fabric of the complex was lost over subsequent centuries as Dublin expanded and rebuilt across its medieval footprint.

The site today falls within the dense urban fabric of Dublin's south inner city, and there is no surviving above-ground trace of the abbey or its associated structures. Visitors interested in the broader medieval topography of the area will find some interpretive context in nearby institutions, and the street pattern in places still faintly echoes earlier boundaries. The gallows itself left no known physical mark; its significance is archival rather than visible. Anyone researching the history of ecclesiastical jurisdiction or crime and punishment in pre-Reformation Ireland would do well to follow Clarke's 2002 work as a starting point, since the documentary record is where this particular story now lives entirely.