- An agreement made in the U.S. Congress which allowed Missouri to enter the Union as a state that permitted slavery, admitted Maine as a free state, and prohibited slavery in all Western territories situated above Missouri's southern border. This compromise initiated the long-running sectional conflict over the expansion of slavery, which culminated in the Civil War. It was later nullified by the Kansas-Nebraska Act in 1854 and deemed unconstitutional by the Dred Scott ruling in 1857
- The Missouri Compromise played a crucial role in the balance of free and slave states in the US during the early 19th century.
- The Kansas-Nebraska Act, passed in 1854, led to the repeal of the Missouri Compromise.
- The legal standing of the Missouri Compromise was ultimately challenged in the controversial Dred Scott decision.