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.
John McCain
McCain was born in the Panama Canal Zone. Had he been elected, he would have become the first president who was born outside the contiguous forty-eight states. This raised a potential legal issue, since the United States Constitution requires the president to be a natural-born citizen of the United States. A bipartisan legal review, and a unanimous but non-binding Senate resolution, both concluded that he was a natural-born citizen. If inaugurated in 2009 at the age of 72 years and 144 days, he would have been the oldest person to become president.