The rath at Tarmon, in north Kerry, does the opposite. It sits in low-lying, somewhat boggy terrain, the kind of ground that early medieval farmers would typically have avoided for a permanent enclosure. That choice, or constraint, gives the site an unusual quality among its type.

A rath is a ringfort defined by earthen banks rather than stone, and this one is classed as univallate, meaning it has a single enclosing bank rather than the two or three concentric rings found at more elaborate examples. The bank here is roughly circular, measuring thirty metres across on its north-south axis and twenty-six metres east to west. Externally it rises to a maximum of 1.7 metres, though on the interior side it stands only about 0.7 metres above the enclosed ground, suggesting the interior has silted or settled over the centuries. The bank base averages five metres wide, and a shallow fosse, the external ditch that provided the material for raising the bank in the first place, runs around the outside, measuring about a metre across and up to a metre deep in places. An east-west fieldbank meets the site at two points without cutting through it, hinting at later agricultural reorganisation of the landscape around the older structure. The bank shows numerous cattle breaks where animals have pushed through over generations, and no definite original entrance has been identified, which is not uncommon where earthworks have been subject to centuries of grazing pressure.