It sits on a drumlin-like hillock, one of those rounded glacial landforms that dot the Irish midlands and west, and the elevation, modest as it is, gives the site a commanding quality; on a clear day the views extend in every direction.

What survives is a rath, the Irish term for a roughly circular earthen enclosure built during the early medieval period, broadly between the fifth and twelfth centuries, and used most commonly as a defended farmstead. The raised circular area at Clydagh measures about 21.5 metres in diameter and is enclosed by a substantial earthen bank some 4.1 metres wide. That bank still stands to an internal height of 0.8 metres and an external height of 1.75 metres, the outer face rising noticeably higher because the ground outside the enclosure drops away. The western section is the best preserved stretch, while breaks in the bank at the north-east and south-west likely mark original entrance points, gaps that would once have been closed with timber gates or hurdle fencing.