The Emancipation Proclamation was a presidential proclamation and executive order issued by United States President Abraham Lincoln on January 1, 1863, during the Civil War. The Proclamation changed the legal status of more than 3.5 million enslaved African Americans in the secessionist Confederate states from enslaved to free. As soon as a slave escaped the control of his or her owner, either by running away across Union lines or through the advance of federal troops, the person was permanently free. In addition, the Proclamation allowed for the recruitment of former slaves into the paid service of the United States armed forces.

On September 22, 1862, Lincoln issued the preliminary Emancipation Proclamation. Its third paragraph reads:

That on the first day of January, in the year of our Lord, one thousand eight hundred and sixty-three, all persons held as slaves within any State or designated part of a State, the people whereof shall then be in rebellion against the United States, shall be then, thenceforward, and forever free; and the Executive Government of the United States, including the military and naval authority thereof, will recognize and maintain the freedom of such persons, and will do no act or acts to repress such persons, or any of them, in any efforts they may make for their actual freedom.

On January 1, 1863, Lincoln issued the final Emancipation Proclamation. After quoting from the preliminary Emancipation Proclamation, it stated:

I, Abraham Lincoln, President of the United States, by virtue of the power in me vested as Commander-in-Chief, of the Army and Navy of the United States in time of actual armed rebellion against authority and government of the United States, and as a fit and necessary war measure for suppressing said rebellion, do ... order and designate as the States and parts of States wherein the people thereof respectively, are this day in rebellion, against the United States, the following, towit:

Lincoln then listed the ten states still in rebellion, excluding parts of states under Union control, and continued:

I do order and declare that all persons held as slaves within said designated States, and parts of States, are, and henceforward shall be free.... [S]uch persons of suitable condition, will be received into the armed service of the United States.... And upon this act, sincerely believed to be an act of justice, warranted by the Constitution, upon military necessity, I invoke the considerate judgment of mankind, and the gracious favor of Almighty God....

The proclamation was directed to all of the areas in rebellion and all segments of the executive branch (including the Army and Navy) of the United States. It proclaimed the freedom of enslaved people in the ten states in rebellion. Even though it excluded areas not in rebellion, it still applied to more than 3.5 million of the 4 million enslaved people in the country. Around 25,000 to 75,000 were immediately emancipated in those regions of the Confederacy where the US Army was already in place. It could not be enforced in the areas still in rebellion, but, as the Union army took control of Confederate regions, the Proclamation provided the legal framework for the liberation of more than three and a half million enslaved people in those regions. The Emancipation Proclamation outraged white Southerners and their sympathizers, who saw it as the beginning of a race war. It energized abolitionists, and undermined those Europeans who wanted to intervene to help the Confederacy. The Proclamation lifted the spirits of African Americans both free and enslaved; it led many to escape from their masters and get to Union lines to obtain their freedom and to join the Union Army. The Emancipation Proclamation became a historic document because it "would redefine the Civil War, turning it from a struggle to preserve the Union to one focused on ending slavery, and set a decisive course for how the nation would be reshaped after that historic conflict."The Emancipation Proclamation was never challenged in court. To ensure the abolition of slavery in all of the U.S., Lincoln also insisted that Reconstruction plans for Southern states require them to enact laws abolishing slavery (which occurred during the war in Tennessee, Arkansas, and Louisiana); Lincoln encouraged border states to adopt abolition (which occurred during the war in Maryland, Missouri, and West Virginia) and pushed for passage of the Thirteenth Amendment. The Senate passed the 13th Amendment by the necessary two-thirds vote on April 8, 1864; the House of Representatives did so on January 31, 1865; and the required three-fourths of the states ratified it on December 6, 1865. The amendment made slavery and involuntary servitude unconstitutional, "except as a punishment for crime."