1780
Pennsylvania adopts a law that gradually emancipates slaves that are born after 1780 when they turn twenty-eight.
The Massachusetts Constitution is adopted with a freedom clause that is interpreted as abolishing slavery.
Delaware prohibits the importation of slaves.
1783
Maryland prohibits the importation of slaves.
1784
Connecticut and Rhode Island adopt gradual emancipation laws.
North Carolina prohibits the importation of slaves.
1785
New York adopts a gradual emancipation law, prohibits slave importation, and allows slave owners to free their slaves without posting a bond.
1787
Richard Allen founds the African Methodist Episcopal Church in Philadelphia, Pennsylvania.
The Northwest Ordinance prohibits slavery in the Northwest. Later it includes Illinois, Indiana, Ohio, Michigan, and Wisconsin.
1788
The U.S. Constitution is adopted and includes the three-fifths clause, which declares that slaves will be counted as three-fifths of a white person for the purpose of congressional representation.
1793
The cotton gin is invented, which leads to the expansion of slavery in the South.
The first Fugitive Slave Law is passed. It allows slave owners to pursue fugitive slaves across state lines and it becomes a criminal offense to help fugitive slaves.
1794
The slave trade between the U.S. and other countries is prohibited by Congress.
1799
New York adopts a gradual emancipation law.
1800
August - Gabriel Prosser plans a slave insurrection in Richmond Virginia.
U.S. citizens are prohibited from exporting slaves.
1803
The Louisiana territory is purchased from France.
1804
Ohio enacts black codes in an attempt to deter fugitive slaves from coming to the state.
New Jersey adopts a gradual emancipation law.
The Underground Railroad is established.
1807
The British Parliament bans the Atlantic slave trade.
1808
The Atlantic slave trade is banned by the U.S.
Washington enacts black codes.
1815
Britain, France, and the Netherlands agree to ban the slave trade.
1817
Spain signs a treaty agreeing to end the slave trade north of the equator and to end it south of the equator in 1820.
The American Colonization Society is established. Its goal is to help African Americans return to Africa.
Georgia bans the slave trade.
1818
February - Frederick Douglass is born.
1819
Slave trading is declared a capital offense by the U.S.
Blacks are prohibited from learning to read in Virginia.
1820
The Missouri Compromise makes slavery illegal in the Louisiana territory that is north of the Missouri border. Missouri is admitted as a slave state and Maine is admitted as a free state.
1822
Denmark Vesey organizes a slave uprising in Charleston, South Carolina.
The colony of Liberia is founded for freed slaves.
1827
Tennessee bans slave trading.
1829
David Walker publishes the anti-slavery pamphlet, An Appeal to the Colored Citizens of the World.
1831
On August 20, Nat Turner’s rebellion occurs in Southampton, Virginia. Turner and six others kill his master's entire family. In the process, they gain the assistance of 40 slaves who help kill at least 55 white people.
Virginia passes a law that prohibits slaves from gathering at night for religious services.
William Lloyd Garrison founds the anti-slavery paper, The Liberator.
Maria Stewart’s essay, “Religion and the Pure Principles of Morality, The Sure Foundation on Which We Must Build” is published in the The Liberator. Stewart becomes the first African American woman to write a political manifesto.
The Virginia legislature debates emancipation. It is the last time abolition is considered by a southern state until the Civil War.
A North Carolina law prohibits teaching slaves from learning to read and write.
