At Caherbriskaun in County Galway, what was once a substantial enclosure, a caher being a type of stone-walled ringfort, had already lost its south-eastern side before the nineteenth century was out. By the time the second edition of the Ordnance Survey six-inch map was produced in 1896, the structure appeared as an oblong enclosure measuring roughly 65 metres by 20 metres, its long axis running north-east to south-west. Something was already missing even then.

What remains today in the level grassland is considerably less legible. A low oval hillock, running approximately 45 metres east to west and 35 metres north to south, rises only about 0.6 metres above the surrounding ground. Compilers Olive Alcock, Kathy de hÓra, and Paul Gosling, working on the Archaeological Inventory of County Galway, noted with characteristic caution that this modest rise is possibly largely natural. That qualifier carries some weight. The site sits in flat agricultural land where any genuine earthwork would ordinarily stand out, yet what survives is so reduced that it is difficult to say with confidence whether you are looking at the ghost of a settlement boundary or simply at the gentle undulation of a field. The enclosure that once measured more than half the length of a football pitch has, over time, been absorbed almost entirely back into the landscape that surrounded it.