In the United States, abolitionism, the movement that sought to end slavery in the country, was active from the colonial era until the American Civil War, the end of which brought about the abolition of American slavery, except as punishment for a crime, through the Thirteenth Amendment (ratified 1865).
The anti-slavery movement originated during the Age of Enlightenment, focused on ending the trans-Atlantic slave trade, evangelical colonists were the primary advocates for the opposition to slavery and the slave trade, doing so on the basis of humanitarian ethics. Between the Revolutionary War and 1804, laws, constitutions, or court decisions in each of the Northern states provided for the gradual or immediate abolition of slavery. No Southern state adopted similar policies.