The primary outcome of the U.S. Civil War (1861-1865) was the preservation of the Union and the abolition of slavery, fundamentally altering the nation's social, political, and economic landscape. The war concluded with the defeat of the Confederate States and led to the passage of the 13th Amendment, which formally abolished slavery in the United States. Additionally, the conflict spurred the Reconstruction era, aimed at reintegrating Southern states and securing civil rights for formerly enslaved individuals. The war also catalyzed significant shifts in federal government power and initiated a long-term struggle for racial equality, shaping American identity and policies for generations to come.