A roughly circular enclosure, around forty metres across, was recorded on the first edition of the Ordnance Survey six-inch map, the great nineteenth-century mapping project that documented Ireland's landscape before so much of it changed beyond recognition. At Castlegar in County Galway, that mapped outline is now the primary evidence that anything was ever here at all.

Circular enclosures of this kind are among the most common archaeological features in the Irish landscape. They range from the remains of ringforts, which were enclosed farmsteads typically dating from the early medieval period, to prehistoric burial or ceremonial sites, and their precise function is often difficult to determine without excavation. Here, the question of what this particular enclosure once was may never be answered. The eastern portion of the interior has been lost to a large quarry pit, and the enclosing bank or wall has been reduced to a single curving band of vegetation running from the south-west to the north-west. That arc of growth, where plants follow the line of buried or disturbed ground, is the kind of trace that would be easy to walk past without recognising it for what it represents: the ghost of a structure that once defined a space on this level, cleared ground in north Galway.