What sets this one apart is a peculiarity in its layout that was noted as far back as 1934, and a subterranean passage built into its fabric that hints at the layered, practical lives of the people who once occupied it.

The site is roughly circular, measuring 44 metres north to south and 41.3 metres east to west. A ringfort, sometimes called a rath, is an early medieval enclosed farmstead, typically dating from around the fifth to the twelfth century, in which a family and their livestock would have lived within one or more concentric earthen banks and ditches. At Garraunawarrig, the inner bank still stands to an internal height of 1.6 metres, with a fosse, or defensive ditch, separating it from an outer bank that survives to 1.1 metres on the western side. When the scholar Bowman described the site in 1934, he identified it as bivallate, meaning it had two enclosing banks, but noted an unusual feature: that outer bank swings outward to the south to create what amounts to a third bank on that side, giving the fort an irregular, asymmetric profile on its southern approach. That southern portion has since been lost to a farm track, leaving no trace of those additional banks. Built into the surviving inner bank is a souterrain, an underground stone-lined passage or chamber, which would have served for storage or as a place of concealment. The combination of the doubled and locally tripled enclosure with an integrated souterrain suggests a settlement that was carefully designed for both security and practical use.