What is "ringfort"

n. An ancient circular fortification of earth or stone, found especially in Ireland.

Ringforts are circular fortified settlements that were mostly built during the Early Middle Ages up to about the year 1000. They are found in Northern Europe, especially in Ireland. There are also many in south Wales and in Cornwall, where they are called 'Rounds'. Ringforts come in many sizes and may be made of stone or earth. Earthen ringforts would have been marked by a circular rampart (a bank and ditch), often with a stakewall. Both stone and earthen ringforts would generally have had at least one building inside.

In Irish language sources they are known by a number of names: ráth (anglicised rath), lios (anglicised lis; cognate with Cornish lis1), caiseal (anglicised cashel), cathair (anglicised caher or cahir; cognate with Welsh caer, Cornish and Breton ker) and dún (anglicised dun or doon; cognate with Welsh and Cornish din). The ráth and lios was an earthen ringfort; the ráth being the enclosing bank and the lios being the open space within. The caiseal and cathair was a stone ringfort. The term dún was usually used for any stronghold of importance, which may or may not be ring-shaped.

In Ireland, over 40,000 sites have been identified as ringforts and it is thought that at least 50,000 ringforts existed on the island. They are common throughout the country, with a mean density of just over one ringfort within any area of 2 km². It is likely that many have been destroyed by farming and urbanisation. However, many hitherto unknown ringforts have been found thanks to early Ordnance Survey maps, aerial photography, and the archaeological work that has accompanied road-building.

In Cornwall and south Wales, enclosed settlements share many characteristics with their Irish counterparts, including the circular shape and souterrains ( fogous), and their continuing occupation into the early medieval period; the form later influencing the distinctive circular shell-keeps found across the medieval Severnside region. Few Cornish examples have been archaeologically excavated, with the exception of Trethurgy Rounds.