In 1790, 60,000 free African Americans lived in the U.S.; in 1830 there were 300,000; and 500,000 by 1860.

The importation of captives for enslavement was provided for in the U.S. Constitution, and continued to take place on a large scale even after it was made illegal in 1808. The slave system was one of the principal engines of the new nation's financial independence, and it grew steadily until it was abolished by war. In 1790 there were fewer than 700,000 enslaved people in the United States; in 1830 there were more than 2 million; on the eve of the Civil War, nearly 4 million.

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On indentured servants:
Irish were brought over as Indentured servants.
Indentured servants were not considered property, slaves were.
Indentured servitude differed from slavery in that it was a form of debt bondage, meaning it was an agreed upon term of unpaid labor that usually paid off the costs of the servant’s immigration to America. Indentured servants were not paid wages but they were generally housed, clothed, and fed.

https://www.pbs.org/opb/historydetect...