What survives is little more than a slightly raised platform in the ground, oval in plan and measuring roughly 42 metres east to west and 28 metres north to south. Most people would walk across it without a second thought.

The site is believed to be a rath, the most common type of early medieval settlement in Ireland. A rath was typically a circular or oval enclosure defined by an earthen bank and outer ditch, built to enclose a farmstead and its inhabitants, probably dating to somewhere between the sixth and twelfth centuries. Thousands survive across the country in varying states of preservation, though many have been reduced over centuries of agriculture to exactly this kind of faint, ambiguous feature. At Clashaganny, the identification rests partly on the local topography and partly on its designation on the Ordnance Survey six-inch maps, the nineteenth-century series that recorded many such earthworks before further erosion or land clearance obscured them still further. Those maps remain one of the more reliable tools for tracing what the landscape once held, even when the physical evidence has grown hard to read.