Or rather, there was one. Two of the most significant land surveys ever conducted in Ireland both recorded its existence in the 1650s, and then, for all practical purposes, it vanished, leaving behind little more than a pair of archival footnotes and an unresolved location.

The Down Survey, carried out between 1655 and 1656 under the direction of William Petty, was a remarkable and ruthless piece of bureaucratic cartography, undertaken in the aftermath of the Cromwellian conquest to map forfeited Irish lands in enough detail to redistribute them among English soldiers and adventurers. The Civil Survey, conducted between 1654 and 1656, worked in parallel, recording landholdings through sworn testimony from local jurors. Between them, these two surveys documented the Irish landscape with an ambition that had no real precedent, yet the building at Balheary slipped through without being precisely located. It appears in the record, unnamed and unspecified, and that is where the trail ends. Geraldine Stout, who compiled the entry, noted only its presence in both surveys and the absence of any fixed coordinates.

Balheary is a small rural townland near Swords, and the area around it contains traces of settlement from various periods, so the building could have been almost anything, a house, an outbuilding, a structure associated with a landholding that changed hands in the upheaval of the 1650s. There is nothing to visit in any conventional sense, no ruins to locate, no marker to find. What the site offers instead is a particular kind of historical experience, the encounter with a gap in the record, a thing documented but not described, present but not placed. For those interested in the mechanics of how seventeenth-century Ireland was surveyed and parcelled out, the absence itself is instructive.