What was once a complete circular enclosure, clearly marked on the second edition Ordnance Survey 6-inch map, now exists as a semicircular fosse measuring approximately 25 metres in diameter. This surviving northern half of the original monument consists of a defensive ditch about 2 metres wide and half a metre deep, carved into land that slopes gently from north to south.

Ringforts, known locally as raths, were amongst the most common forms of settlement in early medieval Ireland, typically dating from the early Christian period between 500 and 1200 AD. These enclosed farmsteads housed extended families and their livestock, with the circular earthen banks and external fosses providing both practical defence and a statement of social status. The Claggan example, though now only partially preserved, would have originally featured a complete ring of earthworks, possibly topped with a wooden palisade, enclosing timber or wattle and daub buildings where daily life unfolded.

Today, the site lies quietly in good pasture land, overgrown but still discernible to the trained eye. Its documentation forms part of the comprehensive Archaeological Survey of County Donegal, compiled in 1983 by Brian Lacey and his team of archaeologists. This extensive survey catalogued field antiquities from the Mesolithic period through to the 17th century, preserving knowledge of sites like this Claggan ringfort that might otherwise fade from memory as the physical remains gradually merge back into the landscape.