The main reason for the conflict between the North and South in the American Civil War was the issue of slavery. The Southern states relied heavily on an agricultural economy that depended on enslaved labor, while the Northern states, which were more industrialized, sought to limit or abolish slavery. This fundamental disagreement over slavery influenced economic interests, social structures, and moral perspectives, leading to rising tensions. Other contributing factors included states' rights, economic competition, and political power struggles. Ultimately, these unresolved conflicts culminated in the Civil War, which lasted from 1861 to 1865 and resulted in significant transformations for the United States.