No ruin survives, no precise address can be given, and the building's occupants left no record that has since come to light. What remains is the outline of a roof drawn by a surveyor working in the 1650s, a faint mark that confirms something substantial once stood here, even if almost everything else about it is lost.

The map in question is the Down Survey, carried out between 1655 and 1656 under the direction of William Petty. It was an extraordinary undertaking, commissioned by the Cromwellian administration to record land ownership across Ireland in enough detail to facilitate the redistribution of confiscated estates to soldiers and creditors. Petty's teams worked townland by townland, and the resulting maps are among the earliest systematic cartographic records of the Irish landscape. Where surveyors noted a building, they sometimes sketched its general form, and at Dolphin's Barn they recorded a gabled dwelling, the kind of detail that suggests a house of some local consequence rather than a simple cabin. The gabled form, meaning a structure with a pitched roof ending in a triangular wall at each end, was associated with more substantial construction in this period. The area took its name from a family called Dolphin, who held land in this part of south Dublin during the medieval period, and by the time of the survey the barn and whatever settlement had grown around it were already part of an established local geography.

Because the site is described as not precisely located, there is no specific spot to visit or landmark to identify. Dolphin's Barn today is a settled urban neighbourhood, absorbed into the city long ago, and the streetscape offers no obvious trace of the early modern period. For anyone interested in this kind of documentary archaeology, the Down Survey maps themselves are accessible through the Down Survey of Ireland project, which has digitised Petty's original parish and barony maps and made them freely available online. Comparing those maps against modern street plans can be a slow and pleasantly uncertain exercise, the kind that occasionally rewards patience with a glimpse of a field boundary or a townland name that has quietly persisted across four centuries.