There was no Confederacy in 1820.
The debate was whether the territory of Missouri would be admitted to the USA as a slave-state or free soil.
Congress allowed it to enter as a slave-state, on condition that there would be no more new slave-states North of the parallel that marked Missouri's Southern border.
It was in 1861 that the question of Union or Confederate control became an issue. There was sectional violence there throughout the war, but the state did remain loyal.
Confederate
Eventhough Missouri allowed slavery they did not secede or leave the Union. So no Missouri was not on the Confederate flag
Union Territory, it was Lee's second invasion of the North.
Kentucky, W.Virginia, Maryland, and Missouri.
Missouri did secede, in fact callaway county in Missouri is still "technically" seceded from the Union
Missouri, Kentucky, and Maryland all border Confederate states.
Missouri, Kentucky, and Maryland all border Confederate states.
Missouri, Kentucky, and Maryland all border Confederate states.
Part of the Missouri Territory was admitted into the union as the 24th state in 1821.
The multiple objectives of the second invasion of the Union by Confederate General Lee was to expand his territory.
The Tallmadge Amendment requested that the territory known as Missouri become a part of the Union. It also demanded that there be no slavery in Missouri if it was admitted to the Union.
Missouri, Kentucky, and Maryland all border Confederate states.