This is a cashel, a type of ringfort defined not by an earthen bank but by a drystone wall, and the one at Doonyvardan measures roughly 25 metres across internally, which would have been a comfortable enough space for a small farmstead or the household of a local farming family in the early medieval period.

The enclosing wall, now collapsed to a height of between 0.3 and 0.5 metres for most of its circuit and spread to a width of 2 to 3 metres, still shows traces of its original construction in places. At the west and north-west, some of the inner-wall facing survives to a height of 0.7 metres, and there is outer-wall facing visible at the east-north-east, suggesting the wall was once a more substantial double-skinned structure with rubble infill, as was typical of cashel building. Much of what remains has been rebuilt in relatively modern times, making it difficult to read what is original and what is later intervention. The cashel sits within a multiperiod field system, meaning the surrounding landscape carries its own layered history of agricultural use stretching across different eras. The site was recorded on the Ordnance Survey six-inch maps of both 1842 and 1916, marked with the hachured symbol used to indicate an earthwork or enclosure, confirming it was a recognisable feature in the landscape through the nineteenth and early twentieth centuries. Views open out to the east and south-east from the terrace, which may have been one reason the site was chosen in the first place.