The American Civil War began in 1861 and lasted four bitter years that took 625,000 lives, more than all other American wars combined, and destroyed property valued at $5 billion. The immediate causes of the war were slavery and the differences between regions.

Southern states depended on slave labour to produce cotton. The North was an industrial society where slavery was illegal. Immigrants from Europe came to supply the labour needed to work in factories, build the railroads, and settle the West. The South had little industry or manufacturing and was opposed to the higher tariffs placed on the goods it imported. The Southern states seceded from the Union, and seized most of the federal forts within their borders. The firing on Fort Sumter in South Carolina in April 1861 began the Civil War.