Missouri Compromise

Law

3 Stat. 545

measure worked out between the North and the South and passed by the U.S. Congress that allowed for admission of Missouri as a slave state, Maine as a free state, and made free soil all western territories north of Missouri's southern border. It marked the beginning of the prolonged sectional conflict over the extension of slavery that led to the Civil War. It was repealed by the Kansas-Nebraska Act (1854) and declared unconstitutional in the Dred Scott decision of 1857.