At Ballynisky in County Limerick, a ringfort, or rath, once occupied a gentle east-facing slope in what is now open pasture. A rath is a roughly circular earthen enclosure, typically dating from the early medieval period and used as a defended farmstead, and they are among the most common monument types in the Irish landscape. This particular example measured approximately twenty metres in diameter. Today, there is nothing left to see.

The site's paper trail tells a story of gradual erasure. The ringfort was clearly recorded on the Ordnance Survey six-inch map of 1841, depicted as a circular enclosure on the sloping ground. By the time the 1923 revision of the same map was produced, a field boundary had been cut directly through the enclosure, bisecting it. That boundary has since been removed as well. When the site was formally inspected and compiled by Denis Power, with the record uploaded in August 2011, no physical trace of the monument remained. The levelling appears to have been thorough.

There is a certain value in visiting a place like this, not for what can be seen, but for what the sequence of maps reveals about how the Irish countryside has been quietly reorganised over the past two centuries. Agricultural improvement, boundary changes, and the removal of earthworks that were once considered obstructions have together eliminated a significant proportion of the country's early medieval sites. The Ballynisky rath is one data point in that larger pattern. The field itself is in private agricultural land, so access would require the landowner's permission. Anyone with an interest in the cartographic side of the story would do well to compare the 1841 and 1923 OS six-inch sheets side by side before visiting, since the maps now carry more information about this place than the ground does.