I believe Mississippi
Missouri just joined the union as a slave state
Nope, Maine was also a anti-slavery state since the start of it's joining into the Union in 1820. Maine joined the Union from the Compromise of 1820. Missouri wanted to become a slave state, but in order to keep a balance between slave to anti-slave states, Maine was then admitted to the Union as a free state(Missouri Compromise of 1820).
Missouri Compromise
The political balance between slave and free states as of 1819 was disturbed by the territory of Missouri's petition for admission to the Union as a slave state.
alabama, which became a state in 1819, was admitted into the union as a slave state.
a slave state
Missouri just joined the union as a slave state
West Virginia broke apart from the slave state Virginia and joined the Union, but for the most part all slave states were Confederate.
Nope, Maine was also a anti-slavery state since the start of it's joining into the Union in 1820. Maine joined the Union from the Compromise of 1820. Missouri wanted to become a slave state, but in order to keep a balance between slave to anti-slave states, Maine was then admitted to the Union as a free state(Missouri Compromise of 1820).
Fifteen - eleven Confederate, four Union. District of Columbia was a slave-state for the first few weeks of the war, though slave-trading was illegal there. The new state of West Virginia was also a slave-state that had seceded from Virginia and the Confederacy, and joined the Union in 1863.
Under the Missouri Compromise of 1820 Missouri was admitted as a slave state and Maine as a free state.
In 1821, Missouri joined the United States as the 24th state. In 1850, California was admitted as the 31st state. These admissions were part of broader territorial expansions and had significant implications for the balance between free and slave states in the Union.
If Missouri had joined the Union as a slave state in 1818, it would have intensified the sectional conflict between the North and South. This could have accelerated the debates over slavery in new territories and potentially led to earlier divisions within the country. The balance between free and slave states would have been disrupted, possibly prompting more aggressive stances from both sides, contributing to the eventual tensions leading up to the Civil War.
Delaware, Kentucky, Maryland, and Missouri were four slave states that did not secede from the Union. West Virginia, another slave state, seceded from Virginia and joined the Union during the Civil War. it was 4 that didn't secede from the union.
After ten years of independence Texas was still menaced by Mexico and the Commanche. Becoming a US State gave Texas added security. Also, Texas received the same rights as any US state at the time, and Texas was allowed to join the Union as a slave state.
West Virginia - although there was very little slavery there.
No State joined the Union in 1956.