At thirty-eight metres in diameter, this cashel, as stone-built ringforts are known, would once have enclosed a farmstead behind a substantial dry-stone wall, thick enough and high enough to deter cattle raiders and opportunistic neighbours alike. What remains now is largely rubble, though a section on the eastern side still preserves faint traces of the inner and outer wall-facing that would have given the structure its original form.

Cashels of this type are broadly associated with the early medieval period in Ireland, roughly the fifth to the twelfth centuries, and were the everyday settlements of farming families across the island, particularly in the west where stone was more readily available than timber. The double-faced dry-stone construction, two vertical outer skins with rubble packed between them, was a technique that produced walls of considerable mass. In Gortnaporia, that mass has long since slumped into the surrounding landscape, leaving the site more intelligible in plan than in profile. The rock outcrop setting suggests the builders worked around the natural limestone that characterises much of this part of Galway, incorporating the terrain rather than clearing it.