The conflict fought between the Northern and Southern U.S. states is known as the American Civil War, which lasted from 1861 to 1865. The primary causes of the war included disagreements over slavery, states' rights, and economic differences. The Southern states seceded from the Union to form the Confederate States of America, primarily to preserve the institution of slavery. The war saw significant battles and loss of life, ultimately resulting in the defeat of the Confederacy. The Civil War had lasting impacts, including the preservation of the Union, the abolition of slavery through the 13th Amendment, and profound social and political changes in the United States.