December 18, 1865

Thirteenth Amendment to the United States Constitution

Seward certifies the Thirteenth Amendment's ratification

The proclamation changed no vote. Georgia had cast the decisive twenty-seventh ratification twelve days earlier; Seward's signature made it official and public.

18 December 1865: verification, not enactment

Secretary of State William H. Seward issued the official certificate on 18 December 1865, verifying that the Thirteenth Amendment had been ratified and had become part of the Constitution.

The threshold had been reached on 6 December, when Georgia became the twenty-seventh ratifying state — three-fourths of the 36 states then in the Union.

One sentence, and one exception

The amendment prohibited slavery and involuntary servitude throughout the United States and places under its jurisdiction, except as punishment following conviction of a crime.

That exception mattered: constitutional abolition did not prevent coercive labour systems from emerging afterwards through Black Codes and peonage.

Kentucky and Delaware

Its nationwide reach ended legal slavery in Kentucky and Delaware — loyal slave states that the Emancipation Proclamation had never covered, and both of which had rejected the amendment.

How many people were still legally enslaved on that date is not recoverable from any reliable contemporaneous count: Delaware recorded 1,798 enslaved people in the 1860 census, but wartime escape, military enlistment and informal emancipation make the December 1865 number uncertain.

Sources

Researched 23 Aug 2026 6 sources 3 audit passes

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

What the sources leave uncertain

December 6 is the date the ratification threshold was reached; December 18 is the date Seward certified it. Accounts that say slavery became illegal only upon the December 18 proclamation blur that distinction.
No reliable contemporaneous count was found for exactly how many people remained enslaved on December 6 or December 18. Wartime escape, military enlistment, and informal emancipation make estimates difficult; the listed figure of 45,000 should not be repeated without a defensible source.