Because they were fighting against slaves and did not want to make things worse.
It would increase the power of the southern states in the senate.
Missouri is in the Northern Hemisphere. It's part of the United States of America.
Senators from the Northern states also objected to the spread of slavery and the admission of any other slave states into the Union. At the time Missouri asked for admission into the Union, the Senate was equally divided with eleven free states and eleven slave states. The new state of Missouri would add two members to the Senate, thereby giving the slave states a majority in the Senate. The Northern senators also feared that, if Missouri were accepted as a slave state, all of the Louisiana territory might be open for slavery. The Southern states were concerned about prohibition of slavery in the Louisiana territory.
The Northern states were opposed to the Missouri Compromise of 1820. They felt Missouri should not be a slave state as it would give the South more power.
The Northern slave-states of Kentucky and Missouri.
It admitted Maine, the northern region of what was then Massachusetts, into the Union as a separate (free) state. The reason this was done was to balance the number of "slave states" and "free states." This only occurred as a result of a compromise involving slavery in Missouri, and in the federal territories of the American west.
Iowa borders the entire northern edge of Missouri.
Maryland and Delaware. There were also Kentucky and Missouri, that we might classify as Northern, as they fought for the Union (the North) in the war.
Northern and southern states
After 1854, the Missouri Compromise, which was the attempt to balance the number of free states and slave states between the Northern and Southern states of the United States, was relinquished and replaced by the Kansas-Nebraska Act.
The two states that touch Oklahoma's northern border are Kansas to the north and Missouri to the northeast. Kansas lies directly above Oklahoma, while Missouri is situated to the northeast of the state.
Northern and southern states