That gap between the historical record and the present-day site is what makes Cathair Deargáin Theas quietly compelling.

The site is a univallate rath, meaning a roughly circular enclosure defined by a single earthen or stone bank, of the kind built across Ireland during the early medieval period as farmstead enclosures. It sits on the gentle north-westerly slopes of Reenconnell, with open views across the northern side of the western Dingle Peninsula. In 1838, the antiquarian John Windele noted caves inside the enclosure, reached by passing under what he described as a kind of gallery covered with stone at the centre. A souterrain, in other words, the term used for the dry-stone underground chambers and passages associated with many Irish raths, which may have served for storage, refuge, or both. T. J. Westropp returned to the subject in 1897 and also mentioned souterrains at the site. Yet when the Dingle Peninsula was systematically surveyed in the 1980s, no souterrain could be identified above ground. Whether the passages have collapsed, been deliberately filled, or are simply obscured under accumulated vegetation and soil is not recorded.