Kansas Territory
The Territory of Kansas was an organized incorporated territory of the United States that existed from May 30, 1854, until January 29, 1861, when the eastern portion of the territory was admitted to the Union as the state of Kansas.
Montana County, Kansas Territory
Following the Republican Party election victories in 1860, the United States Congress admitted Kansas to the Union. The Kansas Act of Admission excluded the portion of the Kansas Territory west of the 25th meridian west from Washington from the new state, and Montana County and the rest of this region reverted to unorganized territory.