Dunguaire Castle is a 16th-century "tower house," built around 1520 by the O'Hynes clan. The castle consists of a tower approximately 23 meters high, surrounded by a defensive wall. The name is derived from the "Dun" (fort) of King Guaire, a legendary 7th-century king of Connacht. Visitors can climb the four floors of the tower for a panoramic view of the bay.

Owner Oliver St. John Gogarty turned the castle into a meeting place for famous writers such as W.B. Yeats, George Bernard Shaw, and Lady Gregory.

The castle served as a backdrop for films such as the Disney production Guns in the Heather (1969) starring Kurt Russell.