Humanities › History & Culture International Trade of Enslaved People Outlawed Act of Congress In 1807 Outlawed Importation of Enslaved People Share Flipboard Email Print Diagram of a ship carrying enslaved people, depicting how humans were loaded to cross the Atlantic Ocean. Getty Images History & Culture African American History The Institution of Slavery & Abolition The Black Freedom Struggle Major Figures and Events Important Figures Civil Rights Segregation and Jim Crow American History African History Ancient History and Culture Asian History European History Genealogy Inventions Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More By Robert McNamara History Expert Robert J. McNamara is a history expert and former magazine journalist. He was Amazon.com's first-ever history editor and has bylines in New York, the Chicago Tribune, and other national outlets. our editorial process Robert McNamara Updated June 30, 2018 The importation of enslaved Africans was outlawed by an act of Congress passed in 1807, and signed into law by President Thomas Jefferson. The law was rooted in an obscure passage in the U.S. Constitution, which had stipulated that importing enslaved people could be prohibited 25 years after the ratification of the Constitution. Though the end of the international trade of enslaved people was a significant piece of legislation, it actually did not change much in a practical sense. The importation of enslaved people had already been decreasing since the late 1700s. However, had the law had not gone into effect, the importation of enslaved people many have accelerated as the growth of the cotton industry accelerated following the widespread adoption of the cotton gin. It's important to note that the prohibition against importing enslaved Africans did nothing to control the domestic traffic and the interstate trade of enslaved people. In some states, such as Virginia, changes in farming and the economy meant enslavers did not need great numbers of enslaved people. Meanwhile, planters of cotton and sugar in the Deep South needed a steady supply of new enslaved people. So a thriving business developed in which captives would typically sent southward. It was common for enslaved people to be shipped from Virginia ports to New Orleans, for instance. Solomon Northup, the author of the memoir Twelve Years a Slave, endured being sent from Virginia to bondage on Louisiana plantations. And, of course, an illegal traffic in trading of enslaved people across the Atlantic Ocean still continued. Ships of the U.S. Navy, sailing in what was called the African Squadron, were eventually dispatched to defeat the illegal trade. The 1807 Ban on Importing Enslaved People When the US Constitution was written in 1787, a generally overlooked and peculiar provision was included in Article I, the part of the document dealing with the duties of the legislative branch: Section 9. The migration or importation of such persons as any of the states now existing shall think proper to admit, shall not be prohibited by the Congress prior to the year one thousand eight hundred and eight, but a tax or duty may be imposed on such importation, not exceeding ten dollars for each person. In other words, the government could not ban the importation of enslaved people for 20 years after the adoption of the Constitution. And as the designated year 1808 approached, those opposed to enslavement began making plans for legislation that would outlaw the trans-Atlantic trade of enslaved people. A senator from Vermont first introduced a bill to ban the importation of enslaved people in late 1805, and President Thomas Jefferson recommended the same course of action in his annual address to Congress a year later, in December 1806. The law was finally passed by both houses of Congress on March 2, 1807, and Jefferson signed it into law on March 3, 1807. However, given the restriction imposed by Article I, Section 9 of the Constitution, the law would only become effective on January 1, 1808. The law had 10 sections. The first section specifically outlawed the importation of enslaved people: "Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,That from and after the first day of January, one thousand eight hundred and eight, it shall not be lawful to import or bring into the United States or the territories thereof from any foreign kingdom, place, or country, any negro, mulatto, or person of colour, with intent to hold, sell, or dispose of such negro, mulatto, or person of colour, as a slave, or to be held to service or labour." The following sections set penalties for violations of the law, specified that it would be illegal to fit out ships in American waters to transport enslaved people, and stated that the U.S. Navy would enforce the law on the high seas. In subsequent years the law was often enforced by the Navy, which dispatched vessels to seize ships suspected of carrying enslaved people. The African Squadron patrolled the west coast of Africa for decades, interdicting ships suspected of carrying enslaved people. The 1807 law ending the importation of enslaved people did nothing to stop the buying and selling of enslaved people within the United States. And, of course, the controversy over enslavement would continue for decades, and would not be finally resolved until the end of the Civil War and the passage of the 13th Amendment to the Constitution.