Cahercommaun (), sometimes Cahercommane is a triple stone ringfort on the south-east edge of the Burren area, in Kilnaboy, near the rural village of Carran, in County Clare, Ireland. It was built in the 9th century.
Features
thumb|left|Inner and outer wall of Cahercommaun ringfort
Cahercommaun sits on the edge of an inland cliff facing north overlooking a wooded valley, with three concentric walls reaching to the cliff edge. The inner wall alone used 16,500 tons of stone. The outer wall measures some 350 ft east-west by 245 ft north-south. The inner wall is about 5 ft thick and 4 ft high and rises 12 to 14 feet above the cliff. The innermost wall, which is the thickest, forms an almost complete circle, but the two outer walls (connected with each other by subsidiary walls, like a fan) only form a semicircle. The innermost wall contains three chambers within the wall.
Excavations
In a six-week period in 1934 it was excavated by the Third Harvard Archaeological Expedition, led by Hugh O'Neill Hencken, which found that the roughly circular enclosure contained at least twelve stone buildings at various times, some of which had souterrains. The archaeologists concluded that Cahercommaun would have been home to a group of at least 40 people, and among the artefacts discovered were wooden spindles used in weaving. A silver brooch found in one of the souterrains indicates that the site was already in existence by the 9th century AD. The brooch, similar in design to the Tara brooch, is in the National Museum of Ireland in Dublin.
The excavation uncovered one of the most important Iron Age collections found in Ireland. From the collection, a set of sheep shears and a saddle quern are on loan to the Clare Museum from the Irish Antiquities Division of the National Museum of Ireland. Evidence was found of settlement dating back to the 5th century and 6th century, although the fort was built during the 9th century. The saddle quern dates from the Late Neolithic/Early Bronze Age period. (possibly) of the kingdom of Cashel which controlled or heavily influenced large parts of the Burren in the 9th century. The site was clearly occupied before that period - as was most of the surrounding countryside, which shows numerous signs of habitation since prehistoric times. Whether the exact spot on which the fort now stands was in use earlier is impossible to verify. However, the 5th/6th century artefacts found indicate the presence in that period of at least a small group of people. Hencken thought this number to have reached around 40 to 50 at its peak. There are no signs of occupation past the 10th century.