There were 8 Presidents who owned other human beings while in office.
1. George Washington; Presidency: 1789-1797; State: VA
Did he own slaves? Yes. When George Washington took over Mount Vernon at age 22 there were 18 slaves. When he married he gained control of 200 more which technically belonged to the estate of his wife’s first husband. By 1786 he owned 216 slaves. (Flexner, P.114) While George Washington was serving as President in Philadelphia a Pennsylvania law was passed freeing slaves whose owners had been citizens of the state for six months. George Washington sent his two most valuable slaves home, telling them it was for his wife’s convenience. (Wilkins, P.76) In 1796 Oney (or Ona) Judge ran away to New Hampshire. She was one of George Washington’s slaves and Martha Washington’s personal servant. President George Washington asked the Treasury Secretary and a customs agent for help in getting her back, by force, if necessary - but she never returned. (Wilkins. P.82. Also: Gerson) When George Washington left the presidency he apparently left some house slaves behind in Philadelphia, knowing that under state law they would be quietly freed by having spent a certain amount of time in Pennsylvania. (Flexner) When he died in 1799 his will called for his manservant William Lee to be freed immediately, and given a pension. The other slaves were to be freed when his widow died. Martha chose to free them two years later. According to Abigail Adams this was because Martha Washington feared her life might be in danger, since her death meant freedom for the slaves. (Hirschfield P.214)
2. Thomas Jefferson; Presidency: 1801-1809; State: VA
Did he own slaves? Yes. Thomas Jefferson inherited many slaves. His wife brought a dowry of more than 100 slaves, and he purchased many more throughout his life. At some points he was one of the largest slave owners in Virginia. In 1790 Thomas Jefferson gave his newly married daughter and her husband 1000 acres of land and 25 slaves. (Miller) In 1798 Thomas Jefferson owned 141 slaves, many of them elderly. Two years later he owned 93. (Bigelow, P.537.) One of Thomas Jefferson’s slaves was Sally Hemings, allegedly the half-sister of his deceased wife. During Thomas Jefferson’s presidency a rumor appeared in print that she was his mistress. Thomas Jefferson denied this story, which was also passed on as Hemings family tradition. The youngest of Heming’s six children (and the only one whose paternity can be traced through DNA) definitely descended from the Jefferson line, either through Thomas Jefferson, his brother Randolph, or one of Randolph’s sons. Thomas Jefferson was in the vicinity of SH during each period of conception. (See Miller, P.148-176.) For a discussion of the DNA issue see: http://tinyurl.com/... and http://jeffersondna.com Thomas Jefferson freed one of Heming’s children and allowed another to run away unpursued. Both of them were light enough to successfully pass for White. (See Miller, P.165.) Thomas Jefferson freed five slaves in his will, all members of the Hemings family. Sally was not among them; Thomas Jefferson’s daughter Martha freed her years later. (See Miller, P.168.)
3. James Madison; Presidency: 1809-1817; State: VA
Did he own slaves? Yes. James Madison grew up in a slave-owning family and owned slaves all his life. In 1833 James Madison sold several of his farms but not his slaves. A year later he sold 16 slaves to a relative - with their permission. (Brant, P.637) He did not free his slaves in his will. (Brant P.640)
4. James Monroe; Presidency: 1817-1825; State: VA
Did he own slaves? Yes. JM inherited a slave named Ralph. When he owned the farm Highland he owned 30 to 40 slaves. (James Monroe and Slavery.)
5. Andrew Jackson; Presidency: 1829-1837; State: SC
Did he own slaves? Yes. AJ bought his first slave, a young woman, in 1788.By 1794 his business included slave trading and he had purchased at least 16 slaves. (Remini, P.37, 55) In the 1820s Jackson owned about 160 slaves. (James, P.31) He did not free his slaves in his will.
6. John Tyler; Presidency: 1841-1845; State: VA
Did he own slaves? Yes.
7. James K. Polk; Presidency: 1845-1849; State: NC
Did he own slaves? Yes. In 1832 he had fifteen slaves.
8. Zachary Taylor; Presidency: 1849-1850; State: VA
Did he own slaves? Yes. President Zachary Taylor was the last U.S. President to own slaves while in office.
See the full video here