Ronald Reagan was America’s oldest president, and could be beaten by Donald Trump if he serves two terms.
But who were the country's youngest presidents?
7th – Franklin Pierce
Born in 1804, Pierce became the youngest president in 1853 at the age of 48 years old. As the Democratic candidate, he beat the Whigs’ Winfield Scott in 1852, but lost out in the Democratic primary four years later to James Buchanan who went on to become his presidential successor.
A 2017 C-Span survey of historians ranked Pierce as America’s third worst president; he only performed better than his successor and Andrew Jackson.
6th – Grover Cleveland
Grover Cleveland is in the unique position of being the country’s only non-consecutive president. The Democrat won the election of 1884 and became the country’s 22nd president, lost the 1888 election, but won the 1892 one, also becoming the nation’s 24th president.
He was a former New York state governor, and started his first presidency just before his 48th birthday.
5th – Barack Obama
Obama became president aged 47. He won the Democratic party’s nomination against Hillary Clinton in 2008 and beat Republican John McCain in the general. Four years later, he defeated Mitt Romney to become the Democrats’ second two-term president since Jimmy Carter.
The C-Span table of presidential rankings by historians places him as the country’s twelfth best president of all time.
4th – Ulysses S. Grant
Before becoming president, Grant had no experience of public office, but was the US army’s commanding general during America’s civil war.
The Republican beat Democratic opponent Horatio Seymour in 1868 with 214 of the 294 electoral college votes available. He was aged just 46 years old, and went on to secure a second term four years later.
3rd – Bill Clinton
The husband of recently defeated presidential candidate Hillary Clinton became president aged aged just 46 after the 1992 election when he defeated incumbent president George H. W. Bush. According to the Miller Centre, he presided over a long period of economic growth, but was impeached by the House (although he was later quitted by the senate).
2nd – John F. Kennedy
Kennedy defeated incumbent Republican Vice President Richard Nixon on a wave of optimism and plans for major reforms at the 1960 election. He became president aged 43 years and 236 days old. His presidency was short-lived however, with his assassination on 22nd November 1963 shaking the world and resulting in his VP Lyndon B. Johnson taking over.
Who knows what could have been had JFK continued in power.
America's youngest president – Theodore Roosevelt
Roosevelt became president in September 1901 aged just 42 years and 322 days old. Before becoming president, he served as vice president, only taking the top job after William McKinley’s assassination.
His face is carved into the Mount Rushmore memorial, and he is ranked as the fourth best US president, according to the C-Span 2017 historian rankings, only beaten by his namesake FDR, George Washington and Abraham Lincoln.