What now is Kansas was included in the Louisiana Purchase of 1803. Many of the early expeditions to the west passed through the area. One, headed by Stephen H. Long in 1819-1820, used the term "great American desert" to describe the plains region. That image kept prospective settlers from the region, which was used by the government for reservations for displaced Indians from the East. Migrating Americans using the Oregon and Santa Fe Trail were going through Kansas on their journey.

Pressure developed to open Kansas for settlement. In the early 1850's, Indians were moved to what became Oklahoma and the United States opened Kansas to settlement through the Kansas Nebraska Act of 1854. The territory soon became a near-battleground among opposing sides in the slavery issue. Rival governments developed and violence erupted. Following controversy both within the territory and Congress, the proposed pro -slavery Lecompton Constitution was rejected by the Kansas electorate and Kansas entered the Union in 1861 under the terms of the Wyandotte Constitution.