Proclamation was applied to states that have slave populations.
The Proclamation, also known as Emancipation Proclamation aimed to free all the slave people, it declared "that all persons held as slaves" in the rebellious states "are, and henceforward shall be free." (quote). It was declared by president Abraham Lincoln on January 1, 1863.
The Proclamation applied just to those states that had seceded from the United States.