Final answer:
Most of the United States' black population was concentrated in the South throughout the 1800s, with a large portion enslaved on plantations. A significant free black population also existed, particularly in the Upper South. The end of the international slave trade did not diminish the internal slave trade, which contributed to one of the largest forced migrations in the country.
Step-by-step explanation:
Throughout the 1800s, most of the United States' black population remained concentrated in the South. Prior to the Civil War, many African Americans were enslaved and worked on cotton and tobacco plantations that underpinned the region's economy.
The census of 1800 documented over one million African Americans, nearly 900,000 of whom were slaves. By 1860, this number rose to 4.4 million, with 3.95 million still in bondage. Post-Civil War, the circumstances for many did not significantly improve, as newly freed slaves often continued as poor agricultural workers.
The presence of a large free black population also characterized the antebellum South. More free blacks lived in the South than in the North, with the majority residing in the upper southern states.
Despite the end of the international slave trade in 1808, the internal slave trade within the South led to one of the largest forced migrations in the nation, further entrenching the institution until the Civil War. Urban centers in both the North and South saw the formation of black-owned business districts and other services as segregation took hold.