A cromlech, sometimes used interchangeably with the term dolmen, typically refers to a megalithic structure of upright stones capped by a large horizontal slab, thought to have served a funerary or ritual purpose during the Neolithic or Bronze Age. The presence of stone circles alongside such a structure suggests a site of some ceremonial complexity, where different phases of prehistoric activity may have accumulated over generations.

Stone circles and megalithic tombs of this type are found across Mayo and the wider Connacht region, often associated with communities farming the landscape in the third and second millennia BC. The particular configuration at Knockfarnaght, combining circular arrangements with a cromlech, points to a place that held significance over a long period, though the specific history of this site, its dimensions, the number of stones still standing, and any excavation history, remain thinly documented in publicly available sources at present.