List of presidents of the United States by age
The median age upon accession to the presidency is 55 years and 3 months. This is how old Lyndon B. Johnson was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president at the age of , following William McKinley's assassination; the oldest was Donald Trump, who was old at his inauguration. The youngest person to be elected president was John F. Kennedy, at of age on election day; the oldest was Ronald Reagan, who was old at the time of his election to a second term.
Franklin Pierce
When Franklin Pierce departed New Hampshire for the inauguration, Jane Pierce chose to remain. Pierce, then the youngest man to be elected president, chose to affirm his oath of office on a law book rather than swear it on a Bible, as all his predecessors except John Quincy Adams had done. He was the first president to deliver his inaugural address from memory. In the address he hailed an era of peace and prosperity at home and urged a vigorous assertion of U.S. interests in its foreign relations, including the "eminently important" acquisition of new territories. "The policy of my Administration", said the new president, "will not be deterred by any timid forebodings of evil from expansion." Avoiding the word "slavery", he emphasized his desire to put the "important subject" to rest and maintain a peaceful union. He alluded to his own personal tragedy, telling the crowd, "You have summoned me in my weakness, you must sustain me by your strength."