A significant result of the Civil War was the end of slavery in the United States, formalized by the ratification of the 13th Amendment in December 1865.

This monumental change abolished the legal institution of slavery, which had been a central issue of the conflict. The war also resulted in the preservation of the Union, diminishing the concept of states' rights as a basis for secession. Additionally, it led to significant societal shifts, including the beginnings of the Reconstruction era, aimed at integrating formerly enslaved individuals into American society.