Where the more familiar earthwork ringforts were raised from ditches and ramparts of soil and turf, a cashel was constructed in stone, its circular or roughly circular wall enclosing a domestic space that would have served as a farmstead during the early medieval period, roughly between the fifth and twelfth centuries. Thousands of ringforts of both kinds survive across Ireland, yet each one occupies a specific patch of ground with its own particular history, and the cashel at Finanagh is one of Clare's quieter examples of this enduring form.

Cashels tend to appear in areas where stone was the most readily available building material, and County Clare, with its limestone-rich landscape, is well supplied with them. The Burren to the north of the county is perhaps the most celebrated concentration, but examples occur throughout Clare wherever the underlying geology offered flat slabs and boulders suitable for stacking without mortar. A cashel's wall, sometimes several metres thick at the base, would have defined a zone of safety and ownership for a single farming family and their livestock, a boundary that was social and legal as much as it was physical. Within early Irish law, the enclosure of a homestead was bound up with a person's status and their rights over land and cattle.