What did the the Missouri Compromise do?

The Missouri Compromise of 1820 was a compromise between pro-slavery and anti-slavery factions in Congress agreeing to prohibit slavery in states north of the parallel 36°30' north except in the state of Missouri. Additionally, the state of Maine was allowed to join the Union as a free state. This compromise was passed due to concerns of the creation of the state of Missouri destroying the delicate balance between slave states and free states in Congress.