The trouble is that nobody knows exactly where.

The evidence for these structures comes from the Down Survey, a remarkable cartographic undertaking carried out between 1655 and 1656 under the direction of William Petty. Commissioned by the Cromwellian administration to map forfeited Irish lands in precise detail, the Down Survey produced some of the earliest large-scale maps of the country, and it is on one of these that dwellings are clearly marked at the mouth of the estuary at the southern end of what is now Portmarnock village. The area was then known as Burrow, a name that reflects the low-lying, sandy character of the ground. Beyond the fact of their appearance on that mid-seventeenth-century map, the houses leave no further trace in the written record examined by researcher Geraldine Stout, who compiled this site record in 2011. Whether they were modest vernacular structures or something more substantial, whether they were already ruinous by the time Petty's surveyors arrived or still in active use, is simply not known.

The Burrow area sits along the narrow sandy peninsula that separates the Broadmeadow estuary from the Irish Sea, and it remains a relatively quiet stretch of coastline. The ground here is unstable by nature, shaped by centuries of shifting sand, storm erosion, and tidal movement, which goes some way to explaining why surface traces of early structures are so elusive. A visitor walking the estuary edge at the southern end of Portmarnock village would be moving through the general zone indicated by the Down Survey map, though there is nothing to mark the spot and no excavation has been carried out to fix the location more precisely. The interest here is less in what can be seen and more in the particular quality of uncertainty the site carries, a fragment of early modern habitation recorded once on a surveyor's map and then effectively lost to the landscape.