A crannog is typically a partially or entirely artificial island, usually built in lakes and estuarine waters of Scotland, Wales, and Ireland. Unlike the prehistoric pile dwellings around the Alps, which were built on the shores and not inundated until later, crannogs were built in the water, thus forming artificial islands.
Crannogs were used as dwellings over five millennia, from the European Neolithic Period to as late as the 17th/early 18th century. In Scotland there is no convincing evidence in the archaeological record of Early and Middle Bronze Age or Norse Period use. The radiocarbon dating obtained from key sites such as Oakbank and Redcastle indicates at a 95.4 per cent confidence level that they date to the Late Bronze Age to Early Iron Age.
Wikipedia https://en.wikipedia.org/wiki/Crannog
Coordinates 52°48'38.714" N -8°47'40.558" E