Ewloe Castle lies hidden in woodland. It may have been built around 1150 by Owain Gwynedd, Prince of all Wales, but was converted to stone in about 1210 by Llywelyn the Great. The earliest building was probably the two-storeyed, D-shaped tower that stands in the eastern bailey of a two-bailey enclosure. The curtain walls and circular tower to the west were added by Llywelyn the Last around 1257.