The Eastern Sea Frontier (EASTSEAFRON) was a United States Navy operational command during World War II, that was responsible for the coastal waters from Canada to Jacksonville, Florida, extending out for a nominal distance of two hundred miles. The Commander was designated Commander, Eastern Sea Frontier (COMEASTSEAFRON). Eastern Sea Frontier's commander also served as commander of the Atlantic Reserve Fleet as of 1937-38. Vice Admiral John S. McCain, Jr. served as Commander, Eastern Sea Frontier, 1965–67, and he was relieved by Admiral Andrew McBurney Jackson, who retired in 1969.