Fifty to sixty metres across, it was once a multivallate enclosure, meaning it was defined by multiple concentric banks and ditches rather than a single boundary, a form of earthwork associated in Ireland with settlements, ritual sites, and occasionally high-status farmsteads. By the time anyone thought to document it formally, it was already gone from the surface.

The enclosure was recorded on the Ordnance Survey six-inch map of 1903 to 1904, which means surveyors could still trace its outline at the turn of the twentieth century. An aerial photograph taken in 1974 tells a different story: by that point the site appears to have been quarried into, its banks and ditches reduced and broken up. At some stage a stables, yard, and barn were built directly over what remained. A moated site, a rectangular embanked enclosure of medieval date, survives roughly 250 metres to the north, suggesting this small area of gently rolling Tipperary farmland once held more than one significant feature. The enclosure at Knockkelly itself, however, is now visible only in documents and old maps, a place that exists in the archive rather than in the field.