The Missouri Compromise was passed by the 16th United States Congress on March 3, 1820, and was signed into law by President James Monroe on March 6, 1820. It admitted Missouri as a slave state and Maine as a free state to maintain the balance of power between free and slave states in the Senate. Additionally, it prohibited slavery in the remaining Louisiana Purchase territory north of the 36°30′ parallel, except for Missouri itself. This compromise was a temporary measure to settle sectional tensions over slavery expansion.
