How many Presidents of the United States owned slaves (people who were legally owned by another as property)?

In total, twelve presidents owned slaves at some point in their lives, eight of whom owned slaves while serving as president. George Washington was the first president to own slaves. He was a major slaveholder before, during, and after his presidency. Zachary Taylor was the last president to own slaves during his presidency; and, Ulysses S. Grant was the last president to have owned a slave at some point in his life.

Among the early presidents, owning slaves was a common practice. Regarding the first twelve presidents, only John Adams and John Quincy Adams never owned slaves. Two of the others (Martin Van Buren and William Henry Harrison) did not own slaves while serving as president. Also, James Buchanan is said to have purchased two slaves; but, he immediately made them paid servants.

The issue of slavery in the U.S. has always alienated Americans. President Taylor, actually said owning slaves was a Constitutional right, and he said slave owners like himself would "appeal to the sword if necessary" to keep them. The U.S. Civil War, of course, put that opinion to the test.