It measures roughly sixty metres across in each direction, and for a period it was planted with a mixture of trees enclosed by a fosse, a shallow ditch dug around the perimeter to define the boundary. By the time anyone went to look at it formally, in September 1982, the trees had been cleared and no physical trace of the enclosing bank or wall remained at ground level. What was once a deliberate, carefully shaped feature of a designed landscape had effectively vanished from the surface of the earth, leaving nothing a walker would notice.

The demesne in question belonged to Coole House, the Georgian country house in south County Galway that became famous as the home of Lady Augusta Gregory, the playwright and co-founder of the Abbey Theatre. Designed landscapes, as the term suggests, were the planned ornamental grounds that accompanied grand houses from the eighteenth century onwards, typically combining woodland walks, water features, walled gardens, and precisely placed plantings intended to give the impression of a cultivated but naturalistic setting. The enclosure at Coole fits that tradition: a subrectangular block of mixed trees, defined by a fosse and almost certainly laid out as an ornamental feature in the grounds of the house. The six-inch Ordnance Survey maps, surveyed in the nineteenth century, record it clearly enough, which is now one of the few ways to confirm it ever existed in the form it did. Aerial photography has since revealed the outline of the fosse still faintly pressed into the ground, invisible at eye level but legible from above as a pale crop or soil mark.

Coole House itself was demolished in 1941, and the demesne is now managed as a nature reserve and woodland park. The tree enclosure, stripped of its planting and its earthworks, survives only as a cartographic ghost and an aerial shadow, a small ornamental ambition that outlasted the house it was meant to complement by, at most, a few decades.