Crannogs were constructed by piling timber, stone, peat, and brushwood into shallow lake water, creating a raised platform on which a dwelling or small settlement could be established. The water itself served as a moat of sorts, making these islands defensible and relatively private in a landscape where such things mattered considerably.

The crannog at Beltra Lough sits within a county that has no shortage of early medieval archaeology, and the western lakelands of Connacht were particularly well suited to this kind of settlement. The labour involved in building a crannog was substantial, suggesting that whoever commissioned its construction had access to organised resources, whether that points to a local chieftain, a farming family of some standing, or a monastic community is difficult to say without excavation data or documentary evidence. Many Irish crannogs remained in seasonal or permanent use for centuries, accumulating layers of occupation debris that archaeologists have found enormously informative elsewhere in the country, yielding everything from wooden vessels and leather shoes to evidence of metalworking and animal husbandry.