These structures are found across Ireland in their hundreds, usually associated with nearby settlement sites, and their purposes are still debated, with theories ranging from storage and refuge to ritual use. The one at Tonreagh is recorded as a monument, which means enough survives, or survived, to be formally noted.

Beyond its existence and location, the details of this particular souterrain remain largely out of public reach for the moment. What can be said in general terms is that Kerry has a notable concentration of early medieval underground structures, a reflection of the dense pattern of ringfort settlement that characterised the region during the first millennium AD. Souterrains were typically accessed through a narrow, low entrance, often deliberately awkward to squeeze through, which would have made them defensible or at least difficult to enter quickly. Some Kerry examples are corbelled, meaning the walls lean inward and are topped with capstones rather than built vertically, a technique that requires no mortar and has allowed many such chambers to survive largely intact for over a thousand years.