Which constitutional amendment abolished slavery in the United States, a landmark in America's national history?

The Thirteenth Amendment abolished slavery and involuntary servitude in the United States, except as punishment for a crime after conviction.

Congress passed the amendment on January 31, 1865, and the required number of states ratified it on December 6, 1865. It became the first of the three Reconstruction Amendments adopted after the Civil War.

President Abraham Lincoln had issued the Emancipation Proclamation in 1863, but that proclamation applied primarily to enslaved people in areas rebelling against the Union and relied on wartime authority. The Thirteenth Amendment established a nationwide constitutional prohibition that did not depend on the status of a particular state or wartime region.

The Fourteenth Amendment addressed citizenship and equal protection, while the Fifteenth Amendment prohibited denying voting rights based on race. These amendments are therefore related, but they answered different constitutional questions.