Cashels are among the most characteristic monuments of early medieval Ireland, typically dating from roughly the sixth to the twelfth centuries and serving as enclosed farmsteads for a single family or petty lord. They are especially common in the limestone landscapes of Clare and neighbouring Connacht, where loose field stone made dry-stone construction the practical choice. The Nooan example carries the designation in its very name, cashel being the Irish word for a stone fort, yet the specifics of this particular enclosure remain largely undocumented in any publicly available form.

What can be said with confidence is that cashels of this type were working agricultural enclosures, their thick circular walls providing protection for livestock and household alike during a period when the Irish countryside was organised around a dense web of small, semi-autonomous farming units. Clare's Burren plateau and its fringes are particularly well supplied with such monuments, many of them still standing to considerable height, their walls largely intact after more than a thousand years. The townland name Nooan itself, like so many in Clare, preserves an older Gaelic layer of the landscape, though tracing its precise etymology without further local documentation would be speculative.