Tens of thousands of these circular earthwork enclosures were built between roughly the fifth and twelfth centuries, defined by one or more banks and ditches surrounding a central living area. That so many survive at all, even in ruined form, is largely because later generations left them alone, treating them with a mixture of practical indifference and superstitious caution.

Raths of this kind were typically the homesteads of farming families of modest status, the banks serving less as military defences than as enclosures for livestock and markers of social territory. The choice of a hillside location like Carrick Hill would have been deliberate, offering drainage, visibility across the surrounding land, and a degree of natural prominence that carried its own social meaning. Mayo, with its Atlantic-facing landscape and its layers of pre-Norman settlement, retains a significant number of these monuments, many of them poorly documented and known mainly to those who happen to walk the ground around them.