These circular enclosures, known in Irish as raths, were the typical farmsteads of early medieval Ireland, built between roughly the fifth and twelfth centuries. A bank of earth, sometimes reinforced with a fosse or outer ditch, enclosed a family's dwelling and perhaps a few outbuildings. Tens of thousands of them survive across Ireland in varying states of preservation, and the one at Killeens is among their quiet number.

The rath form was so common across early medieval Ireland that it became woven into the placename fabric of the country, from Rathmore to Rathmines. Kerry, with its dense scatter of ringforts across farmland and hillside alike, reflects a landscape that was intensively settled during that period. Many raths were later associated in folklore with the sí, the fairy mounds, which gave them a degree of protection from being levelled that purely practical monuments rarely enjoyed. Whether the Killeens example carries any such local lore is not currently documented, but the association was widespread enough that a rath surviving into the present day often owes something to that tradition of unease around disturbing them.