There are five Devil's Islands that I can Find,
Devil's Island, a former penal colony in French Guiana in the
Atlantic Ocean.
Devils Island (Wisconsin), one of the Apostle Islands in
Wisconsin in Lake Superior.
Devils Island, Nova Scotia, a Canadian island in the Atlantic
Ocean.
Devil's Island (Saskatchewan), former name for King Island, a
Canadian Island in the Waskesiu Lake.
Devils Island (Montana), an island in the Yellowstone River.