The American Civil War (1861–1865) became inevitable when the South opened fire on Fort Sumter in 1861.
By 1861, there were many obvious differences between the North and South. For example, the South's labor force was primarily agricultural. But less than half of the North's laborers worked in agriculture. The South was rural while the North had most of the largest urban centers. Slavery was an important institution in the South and Southern leaders were almost always slave owners. Although there were many differences between the two regions, the United States was one nation in 1860. Not until shots were fired at Fort Sumter did they become enemies on the battlefield.
There had been numerous factious quarrels between the North and the South before war erupted, and these occurred between 1820 and 1860. In 1820, the Missouri Compromise dealt with the question of slavery in the West.
