No earthwork rises above the soil, no stones break the surface, no obvious feature interrupts the crop. The enclosure exists, in any practical sense, only from the air.

The evidence for it comes from a single aerial photograph taken in 1977, logged under the reference BKS 2743092/3. What the photograph captured were cropmarks, the faint but legible signatures that buried features leave on growing vegetation when differential moisture and soil depth cause crops to ripen unevenly. In dry summers especially, the outlines of filled-in ditches or collapsed walls can ghost up through a field of grain as darker or lighter strips, readable to anyone who knows what to look for. In this case, the cropmarks trace a sub-circular enclosure, a roughly rounded form rather than a geometrically precise ring, with what appear to be internal features visible within it. A second enclosure, catalogued separately, sits approximately 147 metres to the west and can be made out on modern Bing aerial imagery. The two together suggest this corner of Dublin may have seen more concentrated early activity than the bare field surface currently implies, though without excavation the date and function of either enclosure remain unknown. The record was compiled by Geraldine Stout and updated by Christine Baker in January 2015.

For anyone curious enough to seek it out, the site sits in the southwest corner of Broomfield townland. There is genuinely nothing to see at ground level, which is itself part of the point. The interest here is less about what you can observe in person and more about what the archaeological record quietly preserves: the outline of something deliberately built, used, and eventually buried beneath centuries of cultivation, detectable now only because a photographer happened to fly over in the right summer light in 1977.