A ringfort is a circular or roughly circular earthwork enclosure, typically dating from the early medieval period, built as a defended farmstead and used for livestock and habitation. The example at Culliagh measured approximately 25 metres northwest to southeast and 23 metres northeast to southwest, making it a relatively small but typical specimen of the form. By April 2020, aerial imagery suggested it had been levelled entirely, leaving nothing visible above ground.

The enclosure appears on the 1938 edition of the Ordnance Survey six-inch map, recorded there as a subcircular hachured feature, meaning the cartographers used short radiating lines to indicate a raised earthwork or bank. That map entry is now among the few traces of its existence. Whether it was definitively a ringfort remains uncertain; the cautious assessment is that it may have been one, which reflects how much is lost when a monument disappears before it can be properly examined. The site was brought to wider attention by a Mr D. Kilner, without whose observation even this partial record might not exist.