Crannogs are lake dwellings, artificial islands on which people built their homes from the Neolithic period until as late as the 17th century AD.
They were formed by laying down layers of logs, stones, peat and brush, or whatever other material came to hand (including animal bones), to raise a mound out of the water. The fine example at Lough-na-cranagh, Fairhead, has dry stone facing rising up to 7 ft above the water. To the modern eye, Crannogs may seem uncomfortable places to live, and remnants of wooden palisades suggest that they were designed for defence. But is quite possible that they were simply a practical way of building on marshland, and that the lakes developed later.

They can be a rich source of finds, since the prevailing damp preserves perishable substances like wood and leather.