What survives is a single mark on a map, placed there by surveyors working in the mid-seventeenth century, and nothing more.

The evidence comes from the Down Survey, carried out between 1655 and 1656 under the direction of Sir William Petty. It was one of the most ambitious cartographic projects of its era, commissioned by the Cromwellian administration to document landownership across Ireland following the upheavals of the 1640s, with the practical aim of redistributing confiscated land. The surveyors moved townland by townland, recording buildings, boundaries, and land quality in considerable detail. On the map covering Portraine, a dwelling is marked, suggesting a structure of some standing during the sixteenth or seventeenth century. But the survey offers no name, no owner, no further description, and crucially, no precise coordinates. Geraldine Stout, who compiled this record in 2011, notes simply that the dwelling is not precisely located.

For anyone drawn to Portraine today, the village sits on a small peninsula jutting into the Irish Sea, north of Donabate, and is reachable by road through the flat agricultural land of Fingal. The coastline here is low and open, without the drama of cliffs, which perhaps explains why so little medieval or early modern fabric has survived above ground. There is no ruin to visit, no wall to photograph, and no interpretive panel to consult. The interest lies entirely in the absence: a dot on a baroque-era map, unanchored to any surviving physical trace, representing a household that was real enough in the 1650s for a government surveyor to record it, and has since left nothing else behind.