The area of Alabama north of the 31st parallel was part of the original territory of the United States. The northern two-thirds were a part of Georgia until 1802. The southern one-third of the territory north of the 31st parallel was unorganized until 1798 with the creation of Mississippi Territory. The United States claimed the territory south of the 31st parallel as part of the Louisiana Purchase in 1803, but did not formally acquire this territory from Spain until 1812. Alabama Territory was organized from the eastern part of Mississippi Territory on March 3, 1817, with generally the same boundary as the present state. Alabama was admitted to the Union on December 14, 1819, as the 22nd state.