Originally named the Duke of Clarence Strait by George Vancouver in 1793, Clarence Strait is a portion of the Inside Passage in the Alexander Archipelago in Southeast Alaska, separating Prince of Wales Island from Revillagigedo and Annette Islands. It was named for England’s Prince William, the Duke of Clarence. The strait had actually been named Entrada de Nuestra Señora del Carmén by Jacinto Caamaño, who navigated it a year before Vancouver. It is 126 miles/203 km long, between the Dixon Entrance and the Sumner Strait. There are two lighthouses, the Guard Island Light and Lincoln Rocks Light, which served as navigational aids prior to the era of automation.