The main outcomes of the American Civil War included the preservation of the Union, the abolition of slavery, and significant social and economic changes in the United States. The war, which lasted from 1861 to 1865, ended with the defeat of the Confederate States and resulted in the passage of the 13th Amendment, which formally abolished slavery. Reconstruction efforts aimed to integrate freed slaves into society, granting them citizenship and voting rights through the 14th and 15th Amendments. However, these advancements faced substantial resistance, leading to a legacy of racial tensions and inequalities that persisted long after the war.