<P> The median age upon accession to the presidency is roughly 55 years and 6 months , which is about how old Benjamin Harrison was at the time of his inauguration . The youngest person to assume the office was Theodore Roosevelt , who became president following William McKinley 's assassination , at the age of 7004156620000000000 ♠ 42 years , 322 days . The youngest person elected president was John F. Kennedy , who was inaugurated into office at the age of 7004159420000000000 ♠ 43 years , 236 days . Assassinated three years into his term , he became the youngest at the time of leaving office ( 7004169780000000000 ♠ 46 years , 177 days ) ; the youngest person at the time of leaving office after serving a full four - year term was Theodore Roosevelt ( 7004183900000000000 ♠ 50 years , 128 days ) . The oldest person at the time of entering office was Donald Trump , at the age of 7004257880000000000 ♠ 70 years , 220 days ; Ronald Reagan was the oldest person in office , at the age of 7004284730000000000 ♠ 77 years , 349 days when his presidency ended in January 1989 . </P>
<P> The median age upon accession to the presidency is roughly 55 years and 6 months , which is about how old Benjamin Harrison was at the time of his inauguration . The youngest person to assume the office was Theodore Roosevelt , who became president following William McKinley 's assassination , at the age of 7004156620000000000 ♠ 42 years , 322 days . The youngest person elected president was John F. Kennedy , who was inaugurated into office at the age of 7004159420000000000 ♠ 43 years , 236 days . Assassinated three years into his term , he became the youngest at the time of leaving office ( 7004169780000000000 ♠ 46 years , 177 days ) ; the youngest person at the time of leaving office after serving a full four - year term was Theodore Roosevelt ( 7004183900000000000 ♠ 50 years , 128 days ) . The oldest person at the time of entering office was Donald Trump , at the age of 7004257880000000000 ♠ 70 years , 220 days ; Ronald Reagan was the oldest person in office , at the age of 7004284730000000000 ♠ 77 years , 349 days when his presidency ended in January 1989 . </P>
who is the oldest elected united states president
who is the oldest elected united states president
Donald Trump
Donald Trump