The only way to see it at all is from the air, where it appears as a cropmark, an oval ghost pressed into the earth roughly forty metres across at its longest point and thirty metres at its widest. Cropmarks form when buried features such as ditches, banks, or walls affect how vegetation grows above them; in dry summers especially, the differential moisture retention of disturbed soil causes crops or grass to ripen at different rates, tracing the outlines of structures that have long since vanished below ground. What appears here suggests the remains of a bank, though the feature shows up as interrupted sections rather than a continuous line, leaving open questions about whether this was a domestic enclosure, a field boundary, a ceremonial site, or something else entirely.

The enclosure sits roughly three hundred metres south-south-west of Barnadown House, an eighteenth-century farmhouse that gives the area its name. The cropmark was first reported by Jean Charles Caillére, and has since been confirmed across multiple aerial sources, including Ordnance Survey Ireland imagery from 2005 to 2012 and DigitalGlobe coverage from 2011 to 2013. Its oval shape is consistent with a broad category of enclosures found across Ireland, some prehistoric, some early medieval, many still undated. Without fieldwork, it is impossible to say which period this one belongs to, or what its original purpose was. The eighteenth-century farmhouse nearby is almost certainly unrelated, sitting on land that was already carrying this older, quieter mark long before anyone built on it.