In 1820, amid growing sectional tensions over the issue of slavery, the U.S. Congress passed a law that admitted Missouri to the Union as a slave state and Maine as a free state, while banning slavery from the remaining Louisiana Purchase lands located north of the 36º 30' parallel. The Missouri Compromise was a United States federal legislation that stopped northern attempts to forever prohibit slavery's expansion by admitting Missouri as a slave state and Maine as a free state .
