One of these is a circular enclosure roughly eighteen metres across, defined by a double-kerbed wall with a rubble core, sitting on a north-west-facing slope as if it had been there long before anyone thought to build defensive earthworks around the hilltop.

What makes this enclosure particularly interesting is its company. A slightly larger example, around twenty-five metres in diameter, lies only seven metres to the east, and a smaller one sits approximately twenty-two metres to the south-south-west. The three structures form a loose cluster, and scholars Tom Condit and Eoin Grogan have suggested, on the basis of comparisons with similar enclosures elsewhere in the region, that all three date to the middle or late Bronze Age, placing them broadly in the period between roughly 1500 and 600 BC. The enclosures are not hillforts themselves; rather they are modest, walled circular spaces whose precise function remains open to interpretation, though comparable examples from the same period are sometimes associated with settlement or agricultural use. That they sit outside the main defensive line of the later hillfort suggests the landscape around Mooghaun was already being organised and used long before the great ramparts were raised.