Though the trade and sale of slaves continued to be legal inside the united states until the civil war, the "slave trade"—that is, the importation of slaves from africa or any other foreign locale—was made illegal in

Slave trade in the United States was made illegal in march 2, 1807, by the Act Prohibiting Importation of Slaves, and the law took effect in 1808. This law prohibited the importation of saves into the US. President Thomas Jefferson was the promoter of the law, and he had advocated for this law since the 1770s.

The first law banning US ships from participating in slave trade was the Slave Trade Act of 1794, with some colonies, like Virginia, banning slave trade even earlier.