Slavery was an original Muslim institution. Slaves moved from Africa east not from Africa west to the New World. The Portuguese, Dutch, British and French moved the slaves, that were Traded as commodities by their own people, to the New World. The United States had a small roll in the actual movement of slaves compared with the countries above. The Slave trade was winding down when the United States gained its independence, and the abolition movement had started.
Aprox. 12 million slaves came to the New World, 5% or aprox 500,000 ended up in the US. The majority of the slaves were located in South America and the Carib islands.
This history is not taught in the American schools. History as taught in the American Schools is that the United States is responsible for slavery, a complete and utter falsehood. This is one reason for the racial problems in our country, the truth shall set you free.