History of slavery in the United States by state

Following the creation of the United States in 1776 and the ratification of the U.S. Constitution in 1789, the legal status of slavery was generally a matter for individual U.S. state legislatures and judiciaries (outside of several historically significant exceptions including the Northwest Ordinance of 1787, the 1808 Act Prohibiting Importation of Slaves, the 1820 Missouri Compromise, the Fugitive Slave Act of 1850, the Dred Scott v. Sandford decision of 1857, et al.) As such, slavery flourished in some states (mostly southern), and withered on the vine in others (mostly northern). On the whole, the former Thirteen Colonies abolished slavery relatively slowly, if at all, with several Northern states using gradual emancipation systems in which freedom would be granted after so many years of life or service. (Vermont and New York had clear and absolute freedom dates; Massachusetts and New Hampshire were de facto free states with total abolition from the American Revolution forward.)

For many years after the establishment of the republic, new states were admitted in pairs, so-called free state–slave state twins, so that some states entered the Union with guaranteed "free soil" while their twin permitted the continuation and expansion of America's peculiar institution. Fifteen states (in order of admission, Delaware, Georgia, Maryland, South Carolina, Virginia, North Carolina, Kentucky, Tennessee, Louisiana, Mississippi, Alabama, Missouri, Arkansas, Florida, and Texas) never sought to end slavery, and thus bondage and the slave trade continued in those places, and there was even a movement to reopen the transatlantic slave trade. With the admission of California, Oregon, and Iowa as free states, and the prospective admission of Kansas Territory (likely as a free state), with the commensurate increasing political power of free-state legislators in the United States Congress, the political status quo began to disintegrate. This shift convinced the Slave Power's most influential and vocal leaders that secession was the only way to retain long-term control of both their wealth held in slaves and their political power. (Under the Three-Fifths Compromise brokered at the 1787 Constitutional Convention, enslaved people were considered additional population for purposes of apportionment. The prospective end of slavery would have thus deprived slave owners of the disproportionate representation of their interests in the national legislature, relative not just the people they enslaved but to free white male voters in other states.) Ultimately, a massive and devastating four-year-long war resolved the interstate conflict over slavery, and when rebel state governments were finally overwhelmed by force of arms, various civilian and military representatives of the U.S. government emancipated those people who remained legally enslaved. Slavery in the United States was legally abolished nationwide within the 36 newly reunited states under the Thirteenth Amendment to the United States Constitution, effective December 18, 1865.

The federal district, which is legally part of no state and under the sole jurisdiction of the U.S. Congress, permitted slavery until the American Civil War. For the history of the abolition of the slave trade in the district and the federal government's one and only compensated emancipation program, see slavery in the District of Columbia.

• History of slavery in Alaska
• History of slavery in Colorado
• History of slavery in Montana
• History of slavery in Nebraska
• History of slavery in New Mexico
• History of slavery in Oklahoma
• History of slavery in South Dakota
• History of slavery in Utah

• 1860 United States Census § Population of U.S. states and territories
• Border states (American Civil War)
• Slavery in the United States § Geography and demography
• Emancipation Day § United States
• End of slavery in the United States
• History of unfree labor in the United States

• Slavery in the States: Selected Essays (1893–1914). New York: Negro Universities Press. 1969. ISBN 978-08371-2085-0. LCCN 68055929. OCLC 52010. (CT, MO, NC, NJ, NY, RI)
• Jewett, Clayton E.; Allen, John O. (2004). Slavery in the South: A State-by-State History. Greenwood Publishing Group. ISBN 978-0-313-32019-4.
• Rael, Patrick (2015). Eighty-Eight Years: The Long Death of Slavery in the United States, 1777–1865. Athens, Ga.: University of Georgia Press. ISBN 9780820348292.