Slave trade in the United States

(1) Charleston S.C. 4th March 1833 The land of the free & home of the brave watercolor by British naval officer Henry Byam Martin; (2a) Broadside advertising sale of slaves in the rotunda of the St. Louis Hotel in New Orleans (1858), and (2b) postcard depicting the "Old Slave Block" at the St. Louis Hotel in New Orleans (c. 1900); (3a) Manifest of coastwise slave ship from Charleston to Savannah (1843), and (3c) a coffle passing the U.S. Capitol under construction (1825); (4) Richmond Slave Market Auction oil painting by British artist Lefevre James Cranstone (1862); (5a) slaves marching through Kentucky under the American flag, and (5b) 1859 ad for a Montgomery, Alabama slave depot

The internal slave trade in the United States, also known as the domestic slave trade, the Second Middle Passage^[1] and the interregional slave trade,^[2] was the mercantile trade of enslaved people within the United States. It was most significant after 1808, when the importation of slaves from Africa was prohibited by federal law. Historians estimate that upwards of one million slaves were forcibly relocated from the Upper South, places like Maryland, Virginia, Kentucky, North Carolina, Tennessee, and Missouri, to the territories and then-new states of the Deep South, especially Georgia, Alabama, Louisiana, Mississippi, and Arkansas.

Economists say that transactions in the inter-regional slave market were driven primarily by differences in the marginal productivity of labor, which were based in the relative advantage between climates for the production of staple goods. The trade was strongly influenced by the invention of the cotton gin, which made short-staple cotton profitable for cultivation across large swathes of the upland Deep South (the Black Belt). Previously the commodity was based on long-staple cotton cultivated in coastal areas and the Sea Islands.

The disparity in productivity created arbitrage opportunities for traders to exploit, and it facilitated regional specialization in labor production. Due to a lack of data, particularly with regard to slave prices, land values, and export totals for slaves, the true effects of the domestic slave trade, on both the economy of the Old South and general migration patterns of slaves into southwest territories, remain uncertain. These have served as points of contention among economic historians. The physical effect of forced labor (on remote plantation camps plagued with yellow fever, cholera, and malaria), and social-emotional effect of family separation in American slavery, was nothing short of catastrophic.