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.
Angelica Singleton Van Buren
Sarah Angelica Van Buren (née Singleton; February 13, 1818 – December 29, 1877), was the daughter-in-law of the eighth United States President Martin Van Buren. She was married to the President's son, Abraham Van Buren. She assumed the post of First Lady because the president's wife, Hannah Van Buren, had died 17 years earlier and he remained unwed throughout the rest of his life. Although she was never married to a president, she is the youngest woman ever to act as the White House hostess.