Clarence Strait, originally Duke of Clarence Strait, is a strait in southeastern Alaska, in the United States in the Alexander Archipelago. The strait separates Prince of Wales Island, on the west side, from Revillagigedo Island and Annette Island, on the east side. Clarence Strait is 126 miles long, extending from Dixon Entrance to Sumner Strait. M…Clarence Strait, originally Duke of Clarence Strait, is a strait in southeastern Alaska, in the United States in the Alexander Archipelago. The strait separates Prince of Wales Island, on the west side, from Revillagigedo Island and Annette Island, on the east side. Clarence Strait is 126 miles long, extending from Dixon Entrance to Sumner Strait. Moira Sound is on the west side of the strait.