Short answers, pulled from the story.
The District of Columbia Compensated Emancipation Act, signed by President Abraham Lincoln on the 16th of April, 1862, ended slavery in Washington, D.C. It immediately freed 3,185 people and set aside one million dollars to compensate slaveholders who could prove loyalty to the Union.
Abraham Lincoln signed the act on the 16th of April, 1862. It passed the Senate on the 3rd of April by a vote of 29 to 14, and the House of Representatives approved it on April 11.
The bill was written by Thomas Marshall Key, a U.S. Army colonel and former Democratic state senator from Ohio who was serving as General George McClellan's top legal advisor. Senator Henry Wilson of Massachusetts sponsored it in the Senate.
The act set aside one million dollars to compensate slaveholders loyal to the Union, and nearly all of that appropriation was spent. An additional $100,000 was allocated to pay formerly enslaved people $100 each if they chose to emigrate to countries such as Haiti or Liberia.
The Compensated Emancipation Act predated the Emancipation Proclamation by nearly nine months, making it the earlier federal action to free enslaved people. It applied only to the District of Columbia, whereas the Emancipation Proclamation addressed slavery in the Confederate states.
Washington D.C. celebrates Emancipation Day on April 16 to mark the date Lincoln signed the Compensated Emancipation Act in 1862. The city has observed it since 1866 and designated it an official public holiday in 2005, after a council member proposed the change in 2004.