The one at Lisdeen, in County Clare, is a rath, the term used for an earthen ringfort, typically consisting of one or more circular banks and ditches that once enclosed a farmstead during the early medieval period, roughly between the fifth and twelfth centuries. These were not military fortifications in any dramatic sense, but rather enclosed homesteads, protecting a family, their livestock, and their stores from wolves and opportunistic neighbours alike.

Lisdeen itself is a small townland in west Clare, a county whose limestone geology and long Atlantic edge have preserved an unusually dense concentration of early medieval and prehistoric remains. The rath here belongs to a class of monument that once numbered perhaps fifty thousand across Ireland, though a great many have been lost to agriculture and development over the centuries. Those that survive tend to do so because local tradition attached some significance to them, whether as fairy forts, the dwelling places of the aos sí in folk belief, or simply as awkward lumps of ground that were never worth the effort of levelling. That protective reputation has kept more ringforts standing than any heritage designation.