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 term slave depot was commonly used in New Orleans in the 1850s.
Slave trading was often done in business clusters where many trading firms operated in close proximity. Such clusters existed on specific streets (such as Pratt Street in Baltimore, Adams Street in Memphis, or Cherry Street in Nashville), in specific neighborhoods (in the American Quarter in New Orleans, and at Shockoe Bottom in Richmond), or in settlements seemingly dedicated to serving planters seeking new agricultural laborers (such as Forks of the Road market in Natchez, Mississippi, and at Hamburg, S.C., across the river from Augusta, Georgia). Many thousands of other sales took place on the steps of county courthouses (to satisfy judgments, estates and claims), on large plantations, or anywhere else there was a slave owner who needed cash in order to settle a debt or pay off a bad bet.
A slave market could operate without a dedicated jail, and a jail could operate without an associated market. For example, the grand hotels of New Orleans, and the Artesian Basin in Montgomery, Alabama, were important slave markets not known for their prison facilities. A number of slave jails in the Upper South were used for holding people until slave traders had enough for a shipment south, but were only rarely the site of slave sales, in part because the profit for the trader was sure to be higher in the Deep South, closer to the labor-hungry plantations of the cotton and sugar districts.