The Missouri Compromise was a law passed by the United States Congress in 1820. The key provisions of the Compromise were:
1. Missouri would be admitted as a slave state.
2. Maine would be admitted as a free state.
3. Slavery would be prohibited in all new states formed north of the 36°30' parallel (the southern border of Missouri).
These provisions were intended to maintain the balance of power between free and slave states in the United States, and to prevent any one region from gaining too much influence in Congress. The Missouri Compromise was a temporary solution to the issue of slavery in the United States, and was later repealed by the Kansas-Nebraska Act of 1854.