What is a Crannog? Crannogs are a type of ancient lake dwelling found throughout Scotland and Ireland; they were built out in the water as defensive homesteads from 5000 years ago. People continued to build and occupy them periodically until the 17th century ad. The Crannog on Llangorse Lake is the only Crannog to be found in Wales or England. It is situated in the waters of Llangorse Lake, which is the largest natural lake in south Wales. The Crannog was constructed in 916ad, probably by the King of Brycheiniog. The Welsh Crannog Center will provide you with a journey back into Crannog time, an ideal day out for anybody who has an interest in Welsh history, culture, archaeology, wildlife and plant-life