What are the four bordering states of the confederate states and union states?

The four bordering states between the Confederate States and the Union States during the American Civil War were Missouri, Kentucky, Virginia, and Tennessee. Missouri was a border state with significant internal conflict, while Kentucky declared neutrality but was strategically important for both sides. Virginia seceded from the Union to join the Confederacy, and Tennessee was the first state to secede. These states played crucial roles in the war due to their geographic and strategic significance.