At Jenkinstown in County Kilkenny, it turns out to be nothing of the sort. The island, set within one of two ponds roughly 280 metres south of Jenkinstown House, is a deliberate contrivance, a piece of designed landscape rather than a quirk of local geology.

This kind of feature belongs to a tradition of ornamental estate design that became fashionable among the Anglo-Irish landowning class during the eighteenth and nineteenth centuries. Landowners with the means to do so would reshape the ground around their houses, diverting water, planting specimen trees, and constructing artificial islands or mounds to create an impression of natural scenery that was, in fact, carefully managed. Such islands were sometimes purely decorative, and sometimes intended to support a small summerhouse or to provide nesting habitat for wildfowl. At Jenkinstown, the two ponds and their island sit quietly to the south of the main house, remnants of whatever designed landscape once surrounded it.