American Civil War: The District of Columbia Compensated Emancipation Act, a bill ending slavery in the District of Columbia, becomes law.

An Act for the Release of certain Persons held to Service or Labor in the District of Columbia, 37th Cong., Sess. 2, ch. 54, 12 Stat. 376, known colloquially as the District of Columbia Compensated Emancipation Act or simply Compensated Emancipation Act, was a law that ended slavery in the District of Columbia, while providing slave owners who remained loyal to the United States in the then-ongoing Civil War to petition for compensation. Although not written by him, the act was signed by U.S. President Abraham Lincoln on April 16, 1862. April 16 is now celebrated in the city as Emancipation Day.

In the District of Columbia, the slave trade was legal from its creation until it was outlawed as part of the Compromise of 1850. That restrictions on slavery in the District were probably coming was a major factor in the retrocession of the Virginia part of the District back to Virginia in 1847. Thus the large slave-trading businesses in Alexandria, such as Franklin & Armfield, could continue their operations in Virginia, where slavery was more secure.