The one at Killeentierna is a rath, the most common type, formed by one or more roughly circular earthen banks and ditches that once enclosed a farmstead, offering both a boundary and a degree of protection for the family, their livestock, and their stores within.

Raths were typically built and occupied between roughly the fifth and twelfth centuries, functioning less as military fortifications and more as the enclosed homesteads of farming families of some local standing. The word rath itself is Old Irish, and these structures are so woven into the rural fabric that many have survived simply because generations of farmers thought twice before ploughing through them, a combination of practicality and the older, persistent belief that ringforts were fairy forts, places best left undisturbed. Killeentierna, a townland in County Kerry, takes its name from the Irish for the church of Tighearna, suggesting a parish with early ecclesiastical roots, which makes the presence of a rath in the landscape entirely consistent with the broader settlement patterns of the early Christian period in Munster.