A circular enclosure roughly 36 metres in diameter shows up as a cropmark, the kind of ghostly trace that only becomes readable when differential moisture in the soil causes crops above buried features to grow at slightly different rates, producing pale or dark rings in an otherwise uniform field. The buried ditch defining this enclosure is approximately 1.5 metres wide, narrow enough to suggest a boundary rather than a major defensive work, and the whole thing sits quietly below the surface, untouched and unannounced.

Cropmark archaeology of this kind is well established in Ireland, particularly across the flat, well-drained farmlands of Leinster, where aerial survey and satellite imagery have revealed hundreds of enclosures that left no upstanding trace. Circular enclosures as a class are associated with a broad range of periods and uses, from prehistoric settlement and burial to early medieval ringforts, which were the standard farmstead type in Ireland between roughly the fifth and twelfth centuries. The Corballis example sits within the townland of that name in the barony of Nethercross, a historic administrative division covering much of the Fingal peninsula north of Dublin. The site was identified from Google Earth imagery captured on 24 June 2018, and compiled by Christine Baker, with the record uploaded in November 2021. Without excavation, it is not possible to say with certainty what period the enclosure belongs to, or what activities once took place within it.

There is nothing to see at ground level, which is part of what makes this kind of site worth knowing about. The field is private agricultural land, and the enclosure itself is only detectable through remote sensing. The best way to observe it is via satellite imagery platforms, where the cropmark ring can still be made out in favourable summer conditions, particularly during dry spells when soil moisture contrasts are most pronounced. The estuary setting adds some context, since Malahide Estuary has long been a navigable inlet with a history of settlement along its margins, and the slight southerly slope of the field would have provided both drainage and shelter for whoever once marked out this circular boundary in the earth.