A complete list of U.S. Presidents and their terms served is accessible through the Library of Congress. The LOC represents the country's oldest federal cultural institution, and it is the largest library in the world.
George Washington was the first president, serving from 1789 to 1797, before opting not to run for a third term. As of 2015, fourteen presidents have completed two full terms in office – Washington, Thomas Jefferson, James Madison, James Monroe, Andrew Jackson, Ulysses S. Grant, Grover Cleveland, Woodrow Wilson, Franklin Delano Roosevelt, Dwight Eisenhower, Ronald Reagan, Bill Clinton, George W. Bush and Barack Obama.
Cleveland is the only president to serve two nonconsecutive terms, serving from 1885 to 1889 before his second stint from 1893 to 1897. Franklin Delano Roosevelt is the longest-serving president, serving three terms before passing away three months into his fourth in 1945. On Feb. 27, 1951, the 22nd Amendment was ratified, limiting the number of terms an individual may serve as president to two.
Presidents with the shortest tenures in office are William Henry Harrison (31 days), James Garfield (199 days), Zachary Taylor (491 days), Warren G. Harding (881 days), Gerald Ford (895 days), Millard Fillmore (969 days) and John F. Kennedy (1,036 days).
Four U.S. Presidents have been assassinated while in office – Abraham Lincoln, James Garfield, William McKinley and John F. Kennedy. The only U.S. president to resign from office was Richard Nixon; he was succeeded by Gerald Ford on Aug. 9, 1974.