Ernest Sound is a strait in Southeast Alaska, U.S.A. It extends 48 kilometres (30 mi) southwest, from the mouth of Bradfield Canal to Clarence Strait, separating Wrangell and Etolin Islands from the mainland. It was first traversed and charted in 1793 by James Johnstone, one of George Vancouver's officers during his 1791-95 expedition. Vancouver later named it "Prince Ernest's Sound", after Prince Ernest, Duke of Cumberland (later King of Hanover)