Why did not the Emancipation Proclamation free all US slaves?
The final version of US President Lincoln's Emancipation Proclamation was enacted as a war measure. No slaves were "officially" freed until the 13th amendment to the US Constitution abolished slavery. As a matter of practicality, all slaves became free after the end of the Civil War. During the war, slaves that escaped from the South were considered by the Union to be freed. Border states during the war were not effected by the Proclamation.
It only freed the slaves in the Union. It didnt free the slaves in the Confederacy (South) because they had their own President (Jefferson Davis) and they are not going to listen to who they are fighting against.