Which constitutional amendment abolished slavery in the United States?

The Thirteenth Amendment abolished slavery in the United States.

Congress passed the amendment during the final year of the Civil War, when Union leaders wanted abolition to become permanent national law. The Senate approved it on April 8, 1864, and the House followed on January 31, 1865, after an earlier attempt had failed. The required number of states ratified it on December 6, and it was proclaimed part of the Constitution on December 18, 1865.

Its first section prohibited slavery and involuntary servitude throughout the United States. The amendment included an exception for forced labor imposed as punishment for a crime after conviction. That clause later became important in debates over prison labor and other forms of coerced work.

The amendment is often confused with the Emancipation Proclamation. President Abraham Lincoln’s 1863 proclamation applied primarily to enslaved people in areas rebelling against the Union; it did not abolish slavery everywhere. The Thirteenth Amendment provided the nationwide constitutional prohibition, including in loyal slave states such as Kentucky and Delaware.