Emancipation Day is the only official holiday in the District of Columbia to mark the anniversary of the signing of the Compensated Emancipation Act, which president Abraham Lincoln signed on April 16, 1862. It is in commemoration of Lincoln buying all 3,400 slaves in the District in 1862. It is the only compensated emancipation in US history. He did this as a prelude to the Emancipation Proclamation which came 9 months later.