Derreenataggart

One of the portal stones has broken off, and three stones have been re-erected. The circle is a megalithic stone circle of the type known as a Recumbent Stone Circle (RSC), a kind found only in Scotland and in the south-west of Ireland, where it is called a stone circle of the Cork-Kerry series. These circles date to the end of the Neolithic or the beginning of the Bronze Age. In contrast to the Scottish circles, they additionally have a portal of two large stones in the south-west, opposite the recumbent stone, and contain no central cairn.

The only other well-preserved example in the region is the 17-stone circle of Drombeg, west of Skibbereen. The slender menhir of Knockaneroe stands nearby.

A recumbent stone circle incorporates a large monolith, the recumbent, lying on its side. Such circles are found in only two regions: Aberdeenshire in north-east Scotland and the counties of Cork and Kerry. Some archaeologists, such as Aubrey Burl, have linked them with rituals in which moonlight played a central role, since they are aligned with the arc of the southern moon. Excavations at Tomnaverie in Scotland have suggested that no alignment was intended, so this remains a hypothesis.