I saw this last night on FamilySearch – 400 Years of Slavery: When International Slave Trade Reached Mainland North America: https://www.familysearch.org/blog/en/400-years-of-slavery/.
In 1619, a group of kidnapped Africans forcibly disembarked from ships on the shores of colonial Virginia. They were not the first people to be sold into slavery in the New World. But this date marked the first known sale of human beings on what would eventually become the United States mainland.
The Transatlantic Slave Trade Reaches North America
In 1619, about 350 people were forced aboard the Portuguese ship San Juan Bautista in the slave-trading port of Luanda on the West African coast. They had been captured by Portuguese fighters in Angola and marched up to 200 miles to Luanda.
The San Juan Bautista sailed across the notorious Middle Passage of the transatlantic slave trade triangle. Over the previous century, this route had delivered more than half a million captured Africans into slavery in the Caribbean and parts of mainland South America. But the passengers on this particular trip took an unprecedented, forced turn northward. As the San Juan Bautista crossed the Gulf of Mexico toward Veracruz, English privateers attacked. They captured around 50–60 enslaved passengers and transferred them to their own ships, the White Lion and Treasurer. The English ships set a new course for the British North American colonies.