Which states were added in the union in 1820 as a part of a compromise to keep the balance of slave and free state?

In 1820, the Missouri Compromise was enacted, admitting Missouri as a slave state and Maine as a free state. This compromise was designed to maintain the balance between slave and free states in the Union, as Missouri's admission would otherwise tip the balance in favor of slave states. The compromise also established a line at the 36°30′ latitude, north of which slavery was prohibited in the remaining Louisiana Territory.