It is a rath, the Irish term for a ringfort, the most common archaeological monument type in Ireland. These were the farmsteads of early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries, and they took the form of a roughly circular area enclosed by one or more earthen banks and ditches. Thousands survive across the country, yet each one occupies its own particular patch of ground, often slightly elevated, often still visible as a raised ring in pasture, and each one was once someone's home and holding.

Raths were not forts in any military sense, despite the name. They were working farmsteads, the enclosing bank serving to keep livestock in and predators out, and to mark out the social status of the family within. The size and number of banks, known as univallate for a single bank or multivallate for more, gave a rough indication of the occupant's standing. Inside, there would have been timber or wattle structures, perhaps a souterrain, which is an underground stone-lined passage thought to have been used for storage or refuge. The Ballycrighan example sits within a part of Clare that retains a strong concentration of such monuments, a county whose underlying limestone karst and relatively thin soils have in many places preserved early features that might elsewhere have been ploughed away over centuries of intensive agriculture.