As head of the federal government and chief of the executive branch as a whole, The President of the United States is the highest political office in the United States by influence and recognition. The President is also the Commander-in-Chief of the U.S. armed forces, the head of state and the head of government of the United States.

There have been 42 people sworn into office, and 43 Presidencies, due to the fact that Grover Cleveland served two non-consecutive terms and is counted chronologically as both the 22nd and the 24th President. Of the individuals elected as President, four died in office of natural causes, one resigned, and four were assassinated.
The first President was George Washington, who was inaugurated in 1789 after a unanimous Electoral College vote. William Henry Harrison spent the shortest time in office at 32 days. At over twelve years, Franklin D. Roosevelt spent the longest time in office, and is the only President to serve more than two terms. The current incumbent President is George W. Bush, who is serving his second term. His term is scheduled to end with Inauguration Day on January 20, 2009. President-elect Barack Obama then sworn in.

Below is the list of 44 US presidents (included new elected Barack Obama):
1. George Washington, 1789-1797
2. John Adams, 1797-1801
3. Thomas Jefferson, 1801-1809
4. James Madison, 1809-1817
5. James Monroe, 1817-1825
6. John Quincy Adams, 1825-1829
7. Andrew Jackson, 1829-1837
8. Martin Van Buren, 1837-1841
9. William Henry Harrison, 1841
10. John Tyler, 1841-1845
11. James Knox Polk, 1845-1849
12. Zachary Taylor, 1849-1850
13. Millard Fillmore, 1850-1853
14. Franklin Pierce, 1853-1857
15. James Buchanan, 1857-1861
16. Abraham Lincoln, 1861-1865
17. Andrew Johnson, 1865-1869
18. Ulysses Simpson Grant, 1869-1877
19. Rutherford Birchard Hayes, 1877-1881
20. James Abram Garfield, 1881
21. Chester Alan Arthur, 1881-1885
22. Grover Cleveland, 1885-1889
23. Benjamin Harrison, 1889-1893
24. Grover Cleveland, 1893-1897
25. William McKinley, 1897-1901
26. Theodore Roosevelt, 1901-1909
27. William Howard Taft, 1909-1913
28. Woodrow Wilson, 1913-1921
29. Warren Gamaliel Harding, 1921-1923
30. Calvin Coolidge, 1923-1929
31. Herbert Clark Hoover, 1929-1933
32. Franklin Delano Roosevelt, 1933-1945
33. Harry S. Truman, 1945-1953
34. Dwight David Eisenhower 1953-1961
35. John Fitzgerald Kennedy, 1961-1963
36. Lyndon Baines Johnson, 1963-1969
37. Richard Milhous Nixon, 1969-1974
38. Gerald Rudolph Ford, 1974-1977
39. James Earl Carter, Jr., 1977-1981
40. Ronald Wilson Reagan, 1981-1989
41. George Herbert Walker Bush, 1989-1993
42. William Jefferson Clinton, 1993-2001
43. George Walker Bush, 2001-2009
44. Barack Obama, 2009-

See Complete List of pictures and descriptions for all 44 US Presidents.

Few facts on American Presidents
Father-Son Presidents:
After John Adams and John Quincy Adams., the present President George W Bush and his father, George Herbert Walker Bush, are the second father and son both to serve as US president.

Pets:
Different presidents had different pets in White house. But the most unusual pet was an alligator that John Quincy Adams kept because, he said, he enjoyed the spectacle of guests fleeing from the room in terror!

Hefty President who was stuck in the White House bathtub:
William Howard Taft was the nation’s most corpulent chief executive, his weight fluctuating between 300 and 350 pounds during his term in office (1909-1913). Once, after getting immovably lodged in the White House bathtub, he ordered a new one installed, it is large enough for four normal men.