At Cartronbrack in County Longford, a circular enclosure was recorded on the Ordnance Survey six-inch map in its 1914 edition, sitting in a stretch of moderately drained, level pasture. Walk the ground today, however, and there is nothing to see. The enclosure has vanished from the surface entirely.

Circular enclosures of this kind are among the most common archaeological features in the Irish countryside. They typically survive as the remains of a ringfort, a raised rath, or occasionally a burial monument, and they appear in their thousands across the country. What makes the Cartronbrack example notable is precisely its absence. At some point between the early twentieth century, when the cartographers noted it, and the present day, whatever earthwork once defined this circle was levelled, most likely through agricultural improvement of the surrounding pasture. The land is flat and well-drained, the sort of ground that rewards cultivation and that over the decades swallows the low banks and ditches that once marked the edges of an enclosed settlement or farmstead.