The American Civil War (1861-1865) saw the secession of Southern states from the Union. Triggered by deep political, economic, and social differences, particularly over the issues of slavery and states' rights, several Southern states declared their independence, forming the Confederate States of America. The conflict arose from tensions between the North, which opposed the expansion of slavery, and the South, which sought to preserve its agrarian economy dependent on slave labor. The war ultimately resulted in the preservation of the Union and the abolition of slavery, profoundly impacting America's social and political landscape.