The District of Columbia Emancipation Act

"On April 16, 1862, President Abraham Lincoln signed a bill ending slavery in the District of Columbia. Passage of this act came 9 months before President Lincoln issued his Emancipation Proclamation. The act brought to conclusion decades of agitation aimed at ending what antislavery advocates called "the national shame" of slavery in the nation's capital...":
District of Columbia 

The District of Columbia Emancipation Act

"On April 16, 1862, President Abraham Lincoln signed a bill ending slavery in the District of Columbia. Passage of this act came 9 months before President Lincoln issued his Emancipation Proclamation. The act brought to conclusion decades of agitation aimed at ending what antislavery advocates called "the national shame" of slavery in the nation's capital..."
District of Columbia Emancipation