10 of the first 12 U.S. presidents owned slaves, with the only exclusions being the 2nd president John Adams and the 6th president John Quincy Adams, the son of John Adams. George Washington owned an estimated 200 – 600+ slaves, Thomas Jefferson owned an estimated 200 – 600+ slaves, and Zachary Taylor owned an estimated 300 slaves. The U.S. president with the least number of slaves, not including presidents who did not own slaves, is a tie between the 8th president, Martin Van Buren and the 18th US president, Ulysses S. Grant, each owning one slave. It should be noted, 12 U.S. presidents owned slaves at some point in their lives, however of these 12, 8 owned slaves while in office. The last U.S. president to participate within slavery whilst still in office was Zachary Taylor, and the last U.S. president to own an enslaved person at any time was Ulysses S. Grant. The last person enslaved by a U.S. president was William Andrew Johnson, who was enslaved by the 17th U.S. president, Andrew Johnson. It is believed that Johnson paid $500.00 for William Andrew Johnson’s mother, which equates to $19,348.46 as of 2023 when accounting for inflation using the base year of 1850, 10 years after Johnson’s first slave purchase and 15 years before he became president of the U.S.