A crannog, as these constructed dwelling-places are known, was essentially a platform built out into shallow water, typically from timber, stone, peat, and brushwood, and then occupied as a home or fortified refuge. Thousands were built across Ireland and Scotland over a span stretching from the Bronze Age well into the early medieval period, and many remained in use, or were reused, into the seventeenth century. The one at Shanwar is recorded as a monument, and that fact alone tells us something: somebody, at some point, recognised enough of a physical trace to mark the spot on the archaeological map.

Beyond the existence of the site itself, the specific history of this particular crannog, who built it, when it was occupied, and what, if anything, remains visible today, is not currently available in any published form. It sits in that not uncommon category of Irish archaeological monument that has been identified and registered but not yet fully documented in publicly accessible records. Mayo is a county with an exceptionally dense concentration of crannogs, many of them clustered around the lake systems of its interior, and Shanwar adds one more presence to that quiet, waterlogged geography.