Willow island, Missouri River (Google Maps ⧉, OpenStreetMap ⧉)
Referenced In
History of the Expedition under the Command of Captains Lewis and Clark / To the Sources of the Missouri, Thence Across the Rocky Mountains and Down the River Columbia to the Pacific Ocean
by Meriwether Lewis, William Clark"at twenty-one miles is a willow island half a mile in length, on the north side"