Editing History of the United States (section)

===Increasing demand for slave labor===
{{Main|Slavery in the United States}}
[[File:Crowe-Slaves Waiting for Sale - Richmond, Virginia.jpg|thumb|''Slaves Waiting for Sale: Richmond, Virginia'', an 1861 portrait by British painter [[Eyre Crowe (painter)|Eyre Crowe]]]]
During the first two decades after the Revolutionary War, there were dramatic changes in the status of slavery among the states and an increase in the number of [[Free negro|freed blacks]]. Inspired by revolutionary ideals of equality and influenced by their lesser economic reliance on slavery, northern states abolished slavery.

States of the [[Upper South]] made [[manumission]] easier, resulting in an increase in the proportion of [[free blacks]] in the Upper South (as a percentage of the total non-white population) from less than one percent in 1792 to more than 10 percent by 1810. By that date, a total of 13.5 percent of all blacks in the United States were free.<ref>{{Cite book |last=Kolchin |first=Peter |title=American Slavery, 1619–1877 |url=https://archive.org/details/americanslavery10000kolc |year=1993 |publisher=Hill and Wang |location=New York |pages=[https://archive.org/details/americanslavery10000kolc/page/79 79]–81 |author-link=Peter Kolchin}}</ref> In 1807, with four million slaves already in the United States, Congress severed U.S. involvement with the [[Atlantic slave trade]].<ref name="pbs">{{Cite web |date=January 25, 2007 |title=Interview: James Oliver Horton: Exhibit Reveals History of Slavery in New York City |url=https://www.pbs.org/newshour/bb/social_issues/jan-june07/divided_01-25.html |archive-url=https://web.archive.org/web/20131223050216/http://www.pbs.org/newshour/bb/social_issues/jan-june07/divided_01-25.html |archive-date=December 23, 2013 |access-date=February 11, 2012 |website=[[PBS Newshour]]}}</ref>