This subcircular cashel, once enclosed by a stone wall that has largely collapsed, still retains traces of its original structure. Sections of the wall remain visible, and keen observers can spot what appears to be a second wall in the southwestern sector. A modern field fence now skirts the monument along its northeastern edge, whilst a gap in the southern section might mark the original entrance, though centuries of decay make this impossible to confirm.

The real intrigue of Dunacludean lies beneath the surface, where a souterrain winds through the earth. This underground passage system, accessible through three openings (none of which appear to be original), features a stone-built main corridor running east to west that opens into a substantial chamber just west of the cashel's centre. At its deepest point, the floor drops 1.5 metres below ground level, and from here, shorter subsidiary passages branch off to both east and west. Above ground, two circular foundations northeast and southwest of the souterrain likely mark the locations of ancient hut structures, whilst a large stone bearing a circular depression can be found in the eastern section.

The wider landscape around Dunacludean hints at a more extensive settlement. West of the cashel, faint traces suggest the remains of an old field system, indicating this wasn't merely a defensive structure but part of a working agricultural community. The strategic positioning of the site, with its commanding views across the water, would have provided both practical advantages for spotting approaching vessels and a constant connection to the maritime world that shaped so much of Donegal's history.