Donald Trump is one of many sitting and former US presidents to be targeted in an assassination attempt.

The former US President and Republican presidential candidate was grazed by gunfire on the stage of a Pennsylvania rally after loud bangs that sounded like gunshots rang over.

The last assassination attempt on a US President occurred in March 1981 when President Ronald Reagan was returning to his limousine after speaking at the Washington Hilton Hotel when John Hinckley fired six gunshots toward him.

Reagan was seriously injured by a bullet that hit him in the left underarm, breaking a rib and puncturing a lung. He underwent emergency surgery and recovered. Hinkley was immediately arrested, deemed mentally ill, and confined to an institution until being released in 2016.

Motion picture frame showing John F Kennedy with arms raised after being hit by a bullet in 1963.

The most famous assassination in modern times was the shooting of President John F Kennedy in November 1963 in Dallas, Texas.

Kennedy was in an open-top limousine with wife Jacqueline when he was allegedly shot in the back and killed by Lee Harvey Oswald from the sixth floor of the Texas School Book Depository.

Oswald was arrested and charged with the murder of Kennedy and a Dallas policeman, just hours later, then shot and killed in the Dallas police headquarters by local nightclub owner Jack Ruby two days later.

A commission on the assassination concluded Oswald killed the president and the police officer, but many Americans believe there was a plot or cover-up to kill President Kennedy.

The first assassination attempt on an American President occurred in January 1835 when a house painter Richard Lawrence attempted to shoot President Andrew Jackson with two pistols, both of which misfired. Lawrence was found not guilty because of insanity and confined to a mental institution until he died in 1861.

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The 16th US President, Abraham Lincoln, was assassinated in 1865.

President Abraham Lincoln was not so lucky. After dodging a bullet in 1864, he was shot in the back of the head by a Confederate sympathiser John Wilkes Booth at a theatre event in Washington DC on Good Friday, April 14, 1865. After remaining in a coma for nine hours, Lincoln died the following morning.

President James R Garfield survived an assassination attempt in July 1881 for 79 days after being shot before dying, and President William McKinley suffered a similar fate 20 years later in 1901 after being shot twice in the abdomen by anarchist Leon Czolgosz.

Theodore Roosevelt also had a brush with death, nearly four years after he left office and ran in the 1912 presidential election as a member of the Progressive Party. He was shot once in the chest by a saloon-keeper from New York and survived.

Although not a politician, the assassination of civil rights leader Martin Luther King by James Early Ray on April 4, 1968, is every bit a part of America’s political history.