This clan was anciently known as the MacEwans of Otter, and a building known as MacEwen's Castle stood near Kilfinan on the shore of Loch Fyne. They were allied to the MacLachlans and the MacNeils, and in the 12th century owned part of Cowal. Ewen of Otter, from whom the clan takes its name, lived in the 13th century. About 1432 the Campbells acquired Otter and thereafter the power of the MacEwens declined. The name was later found in other parts of Scotland. The MacEwens were hereditary bards to the Clan Campbell.