Citation
Northwest Ordinance, July 13, 1787, FULL TEXT via National Archives
Excerpt
Northwest Territory (Library of Congress)
Art. 6. There shall be neither slavery nor involuntary servitude in the said territory, otherwise than in the punishment of crimes whereof the party shall have been duly convicted: Provided, always, That any person escaping into the same, from whom labor or service is lawfully claimed in any one of the original States, such fugitive may be lawfully reclaimed and conveyed to the person claiming his or her labor or service as aforesaid.