Clonalis House (Irish: Teach Chluain Mhalais), Castlerea, County Roscommon is the ancestral home of the O'Conor Don, who is a direct descendant of the last High King of Ireland, Ruaidrí Ua Conchobair. Clonalis was constructed in 1878 by Charles Owen O'Conor as a replacement for an earlier house on the same site which was frequently damaged by flooding. Built of mass concrete, its design by the renowned Pepys Cockerell is of a mixture of styles drawing on the traditions of Italianate and Queen Anne Style architecture.