Henry Clay’s Missouri Compromise of 1820 prohibited slavery in any future territories carved out of the northern part of the Louisiana Purchase. In 1854, U.S. Senator Stephen A. Douglas, an Illinois Democrat, led Congress in passing a law that would open the possibility of expanding slavery into this area.
The Kansas-Nebraska Act left it up to the voters in the Kansas and Nebraska territories to decide the legal status of slavery. Douglas called this "popular sovereignty." This law enraged many Northerners because it repealed a key provision of the Missouri Compromise and opened the way for organizing future slave states in the West. The Kansas-Nebraska Act also led to the formation of the Republican Party.
Answer: Through their reconstruction treaty the Choctaw and Chickasaw ceded to the United States the Leased District in the western half of their domain for $300,000. The Creek ceded the western half of their lands for $975,168. Some of the land was to be used for rebuilding, and the remainder was to be held in trust.