The Youngest Presidents in U.S. History

Everyone knows that John F. Kennedy was young, but did you know that Theodore Roosevelt was the youngest President in U.S. history? Browse this list to see who were the youngest - and oldest - Presidents in history.

1. Theodore Roosevelt (42 years, 10 months, 18 days)
2. John F. Kennedy (43 years, 7 months, 22 days)
3. Bill Clinton (46 years, 5 months, 1 day)
4. Ulysses S. Grant (46 years, 10 months, 5 days)
5. Barack Obama (47 years, 5 months, 16 days)
6. Grover Cleveland (47 years, 11 months, 14 days)
7. Franklin Pierce (48 years, 3 months, 9 days)
8. James A. Garfield (49 years, 3 months, 13 days)
9. James K. Polk (49 years, 4 months, 2 days)
10. Millard Fillmore (50 years, 6 months, 2 days)
11. John Tyler (51 years, 0 months, 6 days)
12. Calvin Coolidge (51 years, 0 months, 29 days)
13. Franklin D. Roosevelt (51 years, 1 month, 4 days)
14. William H. Taft (51 years, 5 months, 17 days)
15. Chester A. Arthur (51 years, 11 months, 14 days)
16. Abraham Lincoln (52 years, 0 months, 20 day)
17. Jimmy Carter (52 years, 3 months, 19 days)
18. William McKinley (54 years, 1 month, 4 days)
19. Martin Van Buren (54 years, 2 months, 27 days)
20. Rutherford B. Hayes (54 years, 5 months, 0 days)
21. George W. Bush (54 years, 6 months, 14 days)
22. Herbert Hoover (54 years, 6 months, 22 days)
23. Lyndon B. Johnson (55 years, 2 months, 26 days)
24. Warren G. Harding (55 years, 4 months, 2 days)
25. Benjamin Harrison (55 years, 6 months, 12 days)
26. Richard M. Nixon (56 years, 0 months, 11 days)
27. Woodrow Wilson (56 years, 2 months, 4 days)
28. Andrew Johnson (56 years, 3 months, 17 days)
29. George Washington (57 years, 2 months, 8 days)
30. John Quincy Adams (57 years, 7 months, 21 days)
31. Thomas Jefferson (57 years, 10 months, 19 days)
32. James Madison (57 years, 11 months, 16 days)
33. James Monroe (58 years 10 months, 4 days)
34. Harry S. Truman (60 years, 11 months, 4 days)
35. Gerald R. Ford (61 years, 0 months, 26 days)
36. John Adams (61 years, 4 months, 4 days)
37. Andrew Jackson (61 years, 11 months, 17 days)
38. Dwight D. Eisenhower (62 years, 3 months, 6 days)
39. Zachary Taylor (64 years, 3 months, 8 days)
40. George H. W. Bush (64 years, 7 months, 8 days)
41. James Buchanan (65 years, 10 months, 9 days)
42. William H. Harrison (68 years, 0 months, 23 days)
43. Ronald Reagan (69 years, 11 months, 14 days)

* This list contains 42 U.S. Presidents rather than 43 because Grover Cleveland (who had two non-sequential terms in office) has not been counted twice.