There were 4 million enslaved people counted in the 1860 census. That dropped to zero in the 1870 count.

Every 10 years between 1790 and 1870, the federal government conducted a census that included a count of enslaved people in each state. In 1860, the government counted 4 million slaves. That count fell to zero in the 1870 census, but the actual decline was not sudden.

In 1862, during the Civil War, President Abraham Lincoln issued the Emancipation Proclamation, declaring slaves in Confederate states free. Enslaved people in Texas were not proclaimed free until June 19, 1865 — now known as Juneteenth, a date that became a federal holiday this year — after an announcement by a Union general.

Two slave states that remained part of the Union — Delaware and Kentucky — continued to allow the legal practice of slavery until the December 1865 ratification of the 13th Amendment, which abolished slavery in the US.

This visualization shows the number of enslaved people counted in each of the first nine censuses. Texas is circled below because Juneteenth commemorates the end of slavery in that state.

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