Known as Lisgortaphuca or Lios Gort an Phúca, the site sits about 40 metres east of the river at the mouth of Gleann na hUaighe, where the valley cuts southward for almost two miles into the mountains. By the time the Ordnance Survey revisited the area for its second edition, the fort had been downgraded to a "site of", with only a slight curve in a field boundary to suggest anything had ever stood there. That understated verdict turns out to be misleading.

A ringfort is a roughly circular enclosure, typically of early medieval date, defined by one or more earthen banks and ditches and used as a farmstead or place of habitation. What makes Lios Gort an Phúca unusual is how it was built. Rather than simply piling up an earthen bank on level ground, whoever constructed it exploited a natural north-to-south scarp in the landscape, artificially heightening it to create a level interior. The western half of the enclosure is still defined by a drop of 3.7 metres to the field below, which gives a more dramatic sense of the original structure than the surviving bank alone might suggest. The overall diameter is now estimated at at least 34 metres, somewhat larger than the approximately 30 metres recorded in the earlier Ordnance Survey Name Book. Inside, two hut-sites survive in traceable form: one roughly circular, its wall reduced to a low bank of earth and stone with what was probably a southward-facing entrance; the other oval, measuring 3.7 by 3.2 metres internally, its enclosing bank rising just over a metre above the interior floor. About 22 metres to the east of the ringfort, a large mound of earth and stone may represent the material cleared when the interior was levelled, a kind of buried invoice for the labour involved in the original construction. The description of the site was first published by J. Cuppage in the Corca Dhuibhne archaeological survey of 1986.