At Knockhouse in County Waterford, there is a site that exists more convincingly on paper than it does in the field. An oval embanked enclosure, measuring roughly 45 metres north to south and 35 metres east to west, was recorded on the Ordnance Survey six-inch map of 1840, yet standing in the pasture today, on a gentle east-facing slope, there is nothing to see at ground level. The earthwork has either been reduced by centuries of agriculture to the point of invisibility, or it survives only as a subtle surface trace that rewards aerial photography or geophysical survey rather than the naked eye.

Embanked enclosures of this general type are found across Ireland and are understood to be enclosures defined by a raised earthen bank, sometimes accompanied by an external ditch. They vary considerably in date and function, and without excavation it is rarely possible to say whether a given example served as a settlement, a stock enclosure, or something with a ritual or ceremonial purpose. What the 1840 OS mapping tells us is that the feature was legible to the surveyors of that period, which means it was sufficiently intact in the early nineteenth century to be recorded with reasonable confidence. The intervening years of pasture management on that quiet slope have since flattened whatever was once visible to the human eye.