Slave markets and slave jails in the United States were places used for the slave trade in the United States from the founding in 1776 until the total abolition of slavery in 1865. Slave pens, also known as slave jails, were used to temporarily hold enslaved people until they were sold, or to hold fugitive slaves, and sometimes even to "board" slaves while traveling. Slave markets were any place where sellers and buyers gathered to make deals. Some of these buildings had dedicated slave jails, others were negro marts to showcase the slaves offered for sale, and still others were general auction or market houses where a wide variety of business was conducted, of which "negro trading" was just one part.

The internal slave trade in the United States, also known as the domestic slave trade, the Second Middle Passage and the interregional slave trade, 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.