Slavery started in the United States shortly after English colonists first settled in Virginia in 1607. It lasted as a legal institution until the passage of the Thirteenth Amendment in 1865.
Before the establishment of slavery, indentured servitude was widespread. It lasted for several years, regardless of race, and was considered a means of using labor to pay for the costs of transporting someone to the colonies. By the 1700s, court rulings established slavery along racial lines, applying chiefly to Black Americans and people of African descent. The southern colonies were devoted to the labor-intensive cultivation of tobacco, and by the end of the 17th century had proportionally more slaves than the north.
From 1654 until 1865, slavery for life was legal in most of the United States. The majority of slaveholding was in the southern United States, where most slaves were used to cultivate cash crops like tobacco and cotton. According to the 1860 census, 4 million were slaves out of a total population of just over 12 million in the 15 slave states. These slaves were owned by about 400,000 people out of that 12 million. The average number of slaves held by any given owner was ten.
The wealth of the US in the first half of the 19th century was greatly enhanced by the labor of African Americans, but with the victory of the Union in the American Civil War (1861-1865), the slave labor system was abolished in the South. This wrecked the postbellum Southern economy, but cotton production in India and Egypt had already started to threaten the southern economy. Northern industry surged further ahead as a result of the war. 12 million Africans were shipped to the Americas from the 16th to the 19th centuries. 645,000 of these ended up in the United States.