The 1842 Ordnance Survey six-inch map shows a hachured circular enclosure, the standard cartographic shorthand for an earthwork with sloping banks, measuring roughly fifty metres across. Today, nothing of that enclosure survives at ground level. The site was levelled, built over, and the building that replaced it has itself since been abandoned.

A ringfort, sometimes called a rath, is a circular earthen enclosure typically dating from the early medieval period in Ireland, used as a defended farmstead for a family and their livestock. The one at Coolacoosane was of the single-rampart variety, meaning it had one encircling bank and ditch rather than the multiple concentric rings that signal higher status. Writing in 1934, a researcher named Bowman recorded that a Mrs. O'Connell had built her residence directly on the site of the levelled fort, which he measured at approximately thirty-one yards in diameter. That figure aligns closely enough with the earlier OS mapping to confirm they describe the same feature. The house has long since been abandoned, leaving a place that has effectively been erased twice: first by whoever levelled the earthwork, and then by time itself.