13th amendment

"Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction" (Primary Documents in American History)
The 13th amendment was ratified on December 6, 1865.
The emancipation proclamation only freed slaves living in non-union states, whereas the 13th amendment freed all slaves in the US. (PBS: Emancipation Proclamation)

13th amendment political cartoon depicting Lincoln ending slavery