The one at Derreen does neither. It sits quietly in flat pastureland just south of where the Owroe and Inny rivers meet, its double ring of earthworks gradually absorbed into the working landscape around it, modern field walls laid directly across the outer bank as though the whole structure were simply another inconvenience to be routed around.

What survives is a bivallate rath, meaning it was enclosed not by one but by two concentric banks, a design that would have made it a more substantial and defensible settlement than the single-banked ringforts that make up the majority of surviving examples. The outer bank, though gapped in places, still stands roughly a metre high and runs about 2.8 metres wide. Between the two banks lies a flat-bottomed fosse, a defensive ditch, measuring just over three metres across. The inner bank is the more imposing of the two, rising 1.7 metres above the base of the fosse, and along its interior face there are intermittent stretches of drystone walling, a detail that hints at more careful construction than the eroded earthworks alone might suggest. The interior measures roughly 24 metres north to south and 25 metres east to west. Scattered stone lies across the level ground inside, though none of it resolves into any recognisable structure. Nineteenth-century Ordnance Survey mapping recorded a break in both enclosing banks on the eastern side, which would be consistent with an original entrance, but the growth that has taken over that area now makes it impossible to confirm.