This ancient ringfort, measuring roughly 19.6 metres east to west and 23 metres from north-northwest to south-southeast, consists of what remains of a once-substantial defensive wall. The builders cleverly incorporated a natural rock cliff on the northern side into their design, using the landscape itself as part of the fortification. Today, the site presents as a subcircular area enclosed by scattered stones; the remnants of a wall that originally stood about 3.25 metres wide before centuries of collapse and stone robbing reduced it to its current state.

The interior of the cashel reveals intriguing features that hint at its former inhabitants’ daily lives. Against the inner edge of the collapsed wall on the south-southwest side, archaeologists have identified a low, subcircular mound of stones approximately 5.6 metres across and half a metre high. Adjacent to this, another stone rise measuring 3.7 by 3.2 metres and 0.4 metres in height suggests the possible remains of internal structures, perhaps dwellings or storage buildings that once stood within the protective embrace of the cashel walls. A modern field wall now runs along the northwest section, built directly atop the ancient collapse, showing how successive generations have continually reshaped this landscape.

This description comes from the Archaeological Survey of County Donegal, compiled by Brian Lacey and his team in 1983, with updates added when the information was digitised in 2008. The survey represents one of the most comprehensive catalogues of Donegal’s archaeological heritage, documenting sites from the Mesolithic period through to the 17th century, ensuring that even modest sites like this cashel at Drumanoo remain part of Ireland’s recorded archaeological story.