It took a satellite image, captured on a dry spring day in March 2019, to bring it into focus. Under the right conditions, buried or levelled earthworks leave their mark on growing crops as cropmarks, faint differences in the colour and vigour of plants that betray the ditches and banks beneath. What appeared on that image was the curved outline of what appears to be a bivallate enclosure, meaning one defined by two concentric ditches rather than one, stretching approximately 190 metres on its longest axis.

The site was identified and reported by Jean-Charles Caillère, who observed that the north-western to north-eastern perimeter is defined by two fosses, or ditches, roughly five to six metres apart. The inner fosse is wider and deeper than the outer one, a detail that hints at a place of some significance, since the effort involved in digging a double circuit of ditches at this scale was considerable. Large curvilinear enclosures of this kind are generally associated with early medieval Ireland, though without excavation the date and function of this one remain open questions. What makes the Carlow example particularly striking is the likelihood that the enclosure does not stop at the field boundary. If the curved arc of ditches continues logically around to form a complete oval or circle, then Park House and its outbuildings sit squarely within the south-western portion of the original enclosed area. The house, in other words, may have been built inside an ancient monument without anyone involved being aware of it. The eastern portion of the enclosure now lies under tillage, which both preserves the buried archaeology and, in dry summers, helps reveal it.