On a low hillock in Ballybaun, in the north of County Galway, there was once a cashel, a type of ringfort enclosed by a stone wall rather than an earthen bank, probably constructed sometime in the early medieval period when such enclosures served as defended farmsteads for a single family or small community. Today, no visible surface trace of it survives.

The evidence for its existence comes from the first edition of the Ordnance Survey six-inch map, which recorded it as a roughly circular enclosure approximately thirty metres in diameter. That mapping project, carried out in Ireland during the nineteenth century, captured many features of the landscape that have since vanished through agriculture, land clearance, and the general attrition of time. In this case, the surrounding ground has been recently cleared of vegetation, which may have hastened the disappearance of whatever earthwork or stonework remained. The hillock itself persists, but the structure it once held does not.