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File:Slave and Free States before the American Civil War-unbiased.png

The slave and free states as of 1861, with free states in red and slave states in blue.

In the United States of America prior to the American Civil War, a slave state was a U.S. state in which slavery of African Americans was legal, whereas a free state was one in which slavery was either prohibited or eliminated over time. Slavery was one of the causes of the American Civil War and was abolished by the Thirteenth Amendment of the United States Constitution in 1865.


The Northeastern and Mid-Atlantic States, including Massachusetts, New York, Pennsylvania and New Jersey, had legally sanctioned slavery in the 17th, 18th and even part of the 19th centuries, but in the generation or two before the American Civil War, almost all slaves had been emancipated through a series of statutes.

The first U.S. region entirely free of slavery was the Midwest, which was ordained free under the Northwest Ordinance of 1787, passed just before the U.S. Constitution was ratified. The states created from this region—Ohio, Indiana, Michigan, Illinois, Wisconsin and Minnesota —were generally settled by New Englanders and American Revolutionary War veterans granted land there. Because this region was entirely slave free from its inception and separated by the Ohio River from the South—which was pushing an expansion of legal slavery into the West—the concept developed of "free states" in contrast to "slave states." The rural Midwest, at one time in direct East-West rivalry with the Northeastern commercial states, realigned with the Northeastern states, newly free of slavery and together created the amalgamation of states prohibiting slavery, known in the context of the Civil War as the free states.

Anti-slavery settlers in "Bleeding Kansas" in the 1850s were called Free-Staters, because they fought (successfully) to include Kansas in the Union as a free state.

Original state-based abolition efforts[]

Prior to the American Revolution, all of the British North American colonies had slavery, but the Revolutionary War gave impetus to a general anti-slavery sentiment. The Northwest Territory, now known as the Midwest, was organized under the Northwest Ordinance with a prohibition on slavery in 1787. Massachusetts accepted that its 1780 Constitution effectively abolished slavery, and several other northern states adopted statutes requiring gradual emancipation. In 1804, New Jersey became the last state to embark on the course of gradual emancipation.

Northern slave states[]

Significant dates VT PA MA NH CT RI NY NJ
European settlement 1666 1638 1620 1623 1633 1636 1624 1620
First record of slavery c.1760? 1639 1629? 1645 1639 1652 1626 1627
Official end of slavery 1777 1780 1783 1783 1784 1784 1799 1804
Actual end of slavery 1777 c.1845 1783 c.1845? 1848 1842 1827 1865

Conflict over new territories[]

During the War of 1812, the British promised emancipation to slaves that would support their side. By the end of the War of 1812, the momentum for antislavery reform, state by state, appeared to run out of steam, with half of the states having already abolished slavery (Northeast), prohibited from the start (Midwest) or committed to eliminating slavery, and half committed to continuing the institution indefinitely (South).

The potential for political conflict over slavery at a federal level led politicians to be concerned about the balance of power in the U.S. Senate, where each State was represented by two Senators. With an equal number of slave states and free states, the United States Senate was equally divided. As the population of the free states began to outstrip the population of the slave states, leading to control of the House of Representatives by free states, the Senate became the preoccupation of slave state politicians interested in maintaining a Congressional veto over federal policy in regard to slavery. As a result of this preoccupation, slave states and free states were often admitted into the Union in pairs to maintain the existing Senate balance between slave and free.

Missouri Compromise[]

Controversy over whether Missouri should be admitted as a slave state, resulted in the Missouri Compromise of 1820, which specified that Louisiana Purchase territory north of latitude 36° 30', which described Missouri's southern boundary, would be organized as free states and territory south of that line would be reserved for organization as slave states. As part of that compromise, the admission of Maine as a free state was secured to balance Missouri's admission as a slave state.

Status of Texas and the Mexican
Cession states

The admission of Texas and the acquisition of vast new western territories after the Mexican-American War further excited controversy. Although the settled portion of Texas was an area rich in cotton plantations and dependent on slavery, the territory acquired in the Mountain West did not seem hospitable to cotton or slavery. In 1850, California was admitted as a free state, without an additional slave state as balance. This would have created a free state majority in the Senate, except that California agreeably sent one pro-slavery and one anti-slavery senator to Washington, D.C. Thus, the admission of California increased the anxiety of pro-slavery politicians but did not change the balance in the senate.

Last battles[]

The difficulty of identifying any territory which could be organized into additional slave states stalled the process of opening the western territories to settlement, while slave state politicians sought a solution. Efforts were made to acquire Cuba and to annex Nicaragua, both to be slave states. In 1854, the Missouri Compromise of 1820 was repealed, and an effort was initiated to organize Kansas as a slave state. Kansas was paired with Minnesota for admission, but the admission of Kansas as a slave state was blocked because of questions over the legitimacy of its slave state constitution. When the admission of Minnesota proceeded unimpeded in 1858, the balance in the Senate was lost; a loss that was compounded by the subsequent admission of Oregon in 1859.

Slave and free state pairs[]

Before 1812, the concern about balancing slave-states and free states was not profound. This is how the states lined up in 1812:

Slave States Year Free States Year
Delaware 1787 New Jersey
(Slave until 1804)
Georgia 1788 Pennsylvania 1787
Maryland 1788 Connecticut 1788
South Carolina 1788 Massachusetts 1788
Virginia 1788 New Hampshire 1788
North Carolina 1789 New York
(Slave until 1799)
Kentucky 1792 Rhode Island 1790
Tennessee 1796 Vermont 1791
Louisiana 1812 Ohio 1803

Following 1812, and until the Civil War, maintaining the balance of free and slave states within the federal legislature was considered of paramount importance if the Union were to be preserved, and states were typically admitted in pairs:

Slave States Year Free States Year
Mississippi 1817 Indiana 1816
Alabama 1819 Illinois 1818
Missouri 1821 Maine 1820
Arkansas 1836 Michigan 1837
Florida 1845 Iowa 1846
Texas 1845 Wisconsin 1848
(One pro-slavery Senator)
Minnesota 1858
Oregon 1859
Kansas 1861

End of slave states[]

Maryland and the pro-Union government of Missouri abolished slavery during the Civil War. The Thirteenth Amendment to the United States Constitution, ratified December 6, 1865, abolished slavery throughout the United States, ending the distinction. Ratification of the 13th Amendment was a condition of the return of local rule to those states that had declared their secession.

See also[]

  • Border states (Civil War)



External links[]

de:Sklavenstaat fr:État esclavagiste (États-Unis) la:Civitas servilis nl:Slavenstaat no:Slavestat pl:Stany niewolnicze