Hut sites are the foundations or surface traces of former dwellings, sometimes circular, sometimes oval, occasionally little more than a slight depression or a ring of stones that only reveals itself in low winter light or from the air. They can range in date from the Bronze Age to the early medieval period and beyond, and in Mayo's boggy uplands they survive in unusual numbers, preserved by the very conditions that eventually drove people away from them.

The Largan site belongs to a category of monument that Irish archaeology has catalogued extensively but unevenly. Many such sites were identified during aerial surveys or fieldwork programmes that swept large areas quickly, leaving individual entries thin on detail. What can be said is that Mayo as a county holds a remarkable concentration of these traces, partly because its blanket bogs began forming around four to five thousand years ago and in doing so sealed earlier field systems, enclosures, and settlements beneath layers of peat. When the bog is cut or erodes, it gives back what it swallowed, sometimes intact enough to show post holes, hearth stones, or the scorch marks of a long-dead fire.