Cashels are among the most common archaeological monument types in Ireland, with tens of thousands recorded across the country, yet individually they remain poorly understood. Most date to the early medieval period, roughly the sixth to twelfth centuries, and functioned as enclosed farmsteads, their circular walls enclosing a household, its outbuildings, and sometimes a souterrain, an underground stone-lined passage that may have served for storage or refuge. The one at Nooan carries the designation cashel specifically because of its construction material, stone being the practical choice in a county where limestone lies close to the surface and suitable building material is never far from hand.

Clare's landscape is thick with such monuments, particularly across the Burren, where the thin soils and exposed karst have preserved field systems, enclosures, and stone structures that would long ago have been ploughed away in more fertile ground. The precise condition, dimensions, and current state of the Nooan cashel are not fully recorded in publicly available form, which places it among a considerable number of Clare monuments whose details remain to be fully catalogued. What can be said is that the townland name Nooan is likely derived from Irish, and that the presence of a cashel there points to early medieval agricultural settlement in an area that would have supported a small farming household or extended family group within its enclosing walls.