A souterrain, to give it its proper name, is an artificial tunnel or chamber constructed, usually during the early medieval period, from carefully arranged dry-stone walling and large capstones. Hundreds of them survive across Ireland, built by farming communities between roughly the seventh and twelfth centuries. Their precise purpose has long been debated: cold storage, refuge during raids, or simple concealment of valuables are the explanations most commonly offered, and it is likely they served different functions at different times.

Tobermaing itself is a name worth pausing on. The element "tober" derives from the Irish "tobar", meaning a well or spring, suggesting the townland may once have been associated with a local water source, possibly one with sacred or practical significance. Such place-name traces are often the only surface clue that a landscape was once densely inhabited and carefully managed. The souterrain here would have been part of a wider settlement, its entrance probably concealed within or close to a ringfort, the circular earthwork enclosures that were the typical homesteads of early medieval Ireland. Whether that associated enclosure survives above ground at Tobermaing is not recorded in what is currently available.

The honest position with this site is that detailed documentation has not yet been made publicly available. What is known is that a souterrain exists, that it has been recorded, and that it sits in a part of Kerry with a landscape shaped by centuries of early Christian and pre-Norman activity. For now, Tobermaing holds its underground chamber quietly, largely unannounced.