A crannog (; Irish: crannóg [ˈkɾˠan̪ˠoːɡ]; Scottish Gaelic: crannag [ˈkʰɾan̪ˠak]) is typically a partially or entirely artificial island, usually built in lakes, rivers and estuarine waters of Scotland, Wales, and Ireland. Unlike the prehistoric pile dwellings around the Alps that were built on the shores and were inundated only later on, 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, although in Scotland there is currently no convincing evidence in the archaeological record of Early and Middle Bronze Age or Norse Period use. The earliest radiocarbon determinations obtained from key sites such as Oakbank in Loch Tay and Redcastle, Beauly Firth approach the Late Bronze Age to Early Iron Age transition at their widest interpretation; at 2 standard deviations or a 95.4% confidence level: they fall after around 800 BC and so could be considered Late Bronze Age by only the narrowest of margins. Crannogs have been variously interpreted as free- standing wooden structures, as at Loch Tay, although more commonly they exist as brush, stone or timber mounds that can be revetted with timber piles. However, in areas such as the Outer Hebrides of Scotland, timber was unavailable from the Neolithic era onwards. As a result, completely stone crannogs supporting drystone architecture are common there. Today, crannogs typically appear as small, circular islets, often 10 to 30 metres (30 to 100 ft) in diameter, covered in dense vegetation due to their inaccessibility to grazing livestock.
