A crannog is usually a partially or entirely artificial island, usually built in lakes, rivers and estuarine waters of Ireland. Crannogs were built in the water, as artificial islands for security and protection. They were used as dwellings over 5000 years, from the Neolithic Period to as late as the 17th or early 18th century. Crannogs have been constructed as free-standing wooden structures, or more commonly as brush, stone or timber mounds reinforced with timber piles. They often had an hidden underwater path to access them. In Connemara completely stone crannogs supporting drystone architecture are common. Crannogs can be seen as small, circular islets, often 10 to 30 metres (30 to 100 ft) in diameter, covered in dense vegetation and trees.
