Kansas entered the Union as a free state on January 29, 1861. About two hundred years earlier the French Jesuit priests, Jacques Marquette and Louis Joliet, were among the region's earliest European explorers. A map drawn by Marquette in 1673 indicated that the Kanza, Ouchage (Osage), and Paneassa (Pawnee) tribes dominated the area that would become Kansas.
The United States acquired Kansas in 1803 from France as part of the Louisiana Purchase. During its early years as a U.S. possession, the area was part of Indian Territory and was used by the federal government to relocate tribal peoples. In 1854, the Kansas-Nebraska Act allowed the residents to decide if theirs would be a free or slave state.