The result of the U.S. Civil War (1861–1865) was the preservation of the Union, the abolition of slavery, and significant social and political changes in the United States. The conflict culminated in the defeat of the Confederate States and led to the passage of the Thirteenth Amendment, which formally abolished slavery. The war also paved the way for Reconstruction, a challenging era aimed at reintegrating the Southern states and promoting civil rights for newly freed African Americans. This period significantly impacted future social dynamics and legislation in the U.S.