crannog

thumb|A reconstructed crannog near Kenmore, Perth and Kinross, on [[Loch Tay, Scotland]]

A crannog (; ; ) is typically a partially or entirely artificial island, usually constructed in lakes, bogs and estuarine waters of Ireland, Scotland, and Wales. Unlike the prehistoric pile dwellings around the Alps, which were built on shores and not inundated until later, crannogs were built in the water, thus forming artificial islands.