An enlargeable map of the United States after the Louisiana Purchase in 1803An enlargeable map of the United States after the Anglo-American Convention of 1818An enlargeable map of the United States after the Dakota Organic Act of 1861An enlargeable map of the United States after the Montana Organic Act of 1864An enlargeable map of the United States after North Dakota statehood in 1889An enlargeable map of the United States as it has been since 1959