The United States acquired the area of Nebraska from France as part of the Louisiana Purchase in 1803. Nebraska Territory was organized on May 30, 1854, from the northwestern part of Missouri Territory (also called Indian Country or Indian Territory). At the time of its organization, the territory included almost all of present-day Nebraska and parts of Colorado, Montana, North Dakota, and South Dakota. The area of the territory was reduced greatly in 1861 with the organization of Colorado and Dakota territories. Nebraska was admitted to the Union on March 1, 1867, as the 37th state. In 1882, Nebraska acquired from Dakota Territory an area north of the Keya Paha River and Niobrara River to assume generally the same boundary as the present state. Nebraska and Iowa have made periodic adjustments to their boundary as the Missouri River has changed its course.